tag:theconversation.com,2011:/us/topics/anatomy-492/articlesAnatomy – The Conversation2024-03-06T03:32:43Ztag:theconversation.com,2011:article/2248582024-03-06T03:32:43Z2024-03-06T03:32:43ZSome women’s breasts can’t make enough milk, and the effects can be devastating<figure><img src="https://images.theconversation.com/files/580034/original/file-20240305-22-gta22i.jpg?ixlib=rb-1.1.0&rect=0%2C4%2C1000%2C661&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mom-looking-camera-depression-dark-circles-2364312147">Alberto_Rodriguez/Shutterstock</a></span></figcaption></figure><p>Many new mothers worry about their milk supply. For some, support from a <a href="https://www.breastfeeding.asn.au/breastfeeding-helpline">breastfeeding counsellor</a> or <a href="https://www.lcanz.org/resources/clients/what-is-a-lactation-consultant/">lactation consultant</a> helps.</p>
<p>Others cannot make enough milk no matter how hard they try. These are women whose breasts are not physically capable of producing enough milk. </p>
<p>Our recently published <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0299642">research</a> gives us clues about breast features that might make it difficult for some women to produce enough milk. Another of our studies shows the devastating <a href="https://www.sciencedirect.com/science/article/pii/S1877575624000089">consequences</a> for women who dream of breastfeeding but find they cannot.</p>
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<strong>
Read more:
<a href="https://theconversation.com/i-feel-guilty-for-feeling-like-that-one-fifth-of-breastfeeding-women-report-an-aversion-response-208938">'I feel guilty for feeling like that.’ One fifth of breastfeeding women report an aversion response</a>
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<h2>Some breasts just don’t develop</h2>
<p>Unlike other organs, breasts are not fully developed at birth. There are key <a href="https://pubmed.ncbi.nlm.nih.gov/33711581/">developmental stages</a> as an embryo, then again during puberty and pregnancy.</p>
<p>At birth, the breast consists of a simple network of ducts. Usually during puberty, the glandular (milk-making) tissue part of the breast begins to develop and the ductal network expands. Then typically, further growth of the ductal network and glandular tissue during pregnancy prepares the breast for lactation.</p>
<p>But our online <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0299642">survey</a> of women who report low milk supply gives us clues to anomalies in how some women’s breasts develop.</p>
<p>We’re not talking about women with small breasts, but women whose glandular tissue (shown in this diagram as “lobules”) is underdeveloped and have a condition called breast hypoplasia.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Anatomical diagram of the breast" src="https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=492&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=492&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580068/original/file-20240306-20-onsg4t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=492&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sometimes not enough glandular tissue, shown here as lobules, develop.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/mammary-gland-vector-illustration-showing-cross-1550556230">Tsuyna/Shutterstock</a></span>
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<p>We don’t know <a href="https://doi.org/10.1111/jmwh.12070">how common</a> this is. But it has been <a href="https://www.liebertpub.com/doi/abs/10.1089/bfm.2021.0032?journalCode=bfm">linked</a> with lower rates of exclusive breastfeeding. </p>
<p>We also don’t know what causes it, with much of the research conducted <a href="https://pubmed.ncbi.nlm.nih.gov/33711581/">in animals</a> and not humans. </p>
<p>However, certain health conditions have been associated with it, including <a href="https://connect.springerpub.com/highwire_display/entity_view/node/154992/full">polycystic ovary syndrome</a> and other endocrine (hormonal) conditions. A high body-mass index around the time of puberty may be another <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0299642">indicator</a>. </p>
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<p>
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Read more:
<a href="https://theconversation.com/why-do-men-have-nipples-120893">Why do men have nipples?</a>
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</em>
</p>
<hr>
<h2>Could I have breast hypoplasia?</h2>
<p>Our <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0299642">survey</a> and other research give clues about who may have breast hypoplasia. </p>
<p>But it’s important to note these characteristics are indicators and do not mean women exhibiting them will definitely be unable to exclusively breastfeed.</p>
<p>Indicators include:</p>
<ul>
<li><p>a <a href="https://pubmed.ncbi.nlm.nih.gov/33586493/">wider than usual gap</a> between the breasts</p></li>
<li><p><a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0299642">tubular-shaped</a> (rather than round) breasts </p></li>
<li><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6057589/">asymmetric</a> breasts (where the breasts are different sizes or shapes)</p></li>
<li><p>lack of breast growth in pregnancy</p></li>
<li><p>a <a href="https://www.tandfonline.com/doi/full/10.1080/14767058.2023.2214833">delay</a> in or absence of breast fullness in the days after giving birth </p></li>
</ul>
<p>In our survey, 72% of women with low milk supply had breasts that did not change appearance during pregnancy, and about 70% reported at least one <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0299642">irregular-shaped</a> breast.</p>
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<strong>
Read more:
<a href="https://theconversation.com/5-expert-tips-on-how-to-look-after-your-baby-in-a-heatwave-216906">5 expert tips on how to look after your baby in a heatwave</a>
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<h2>The effects</h2>
<p>Mothers with low milk supply – whether or not they have breast hyoplasia or some other condition that limits their ability to produce enough milk – report a range of emotions.</p>
<p>Research, <a href="https://www.sciencedirect.com/science/article/pii/S1877575624000089">including our own</a>, shows this ranges from frustration, confusion and surprise to intense or profound feelings of failure, guilt, grief and despair. </p>
<p>Some mothers describe “<a href="https://bmjopen.bmj.com/content/9/5/e026234">breastfeeding grief</a>” – a prolonged sense of loss or failure, due to being unable to connect with and nourish their baby through breastfeeding in the way they had hoped. </p>
<p>These feelings of failure, guilt, grief and despair can trigger symptoms of <a href="https://www.sciencedirect.com/science/article/pii/S1877575624000089">anxiety and depression</a> for some women.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Tired, stress woman with hand over face" src="https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=316&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=316&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=316&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=397&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=397&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580048/original/file-20240306-24-lhznqd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=397&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Feelings of failure, guilt, grief and despair were common.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tired-mother-rubbing-face-while-breastfeeding-2371946203">Bricolage/Shutterstock</a></span>
</figcaption>
</figure>
<p>One woman told us:</p>
<blockquote>
<p>[I became] so angry and upset with my body for not being able to produce enough milk.</p>
</blockquote>
<p>Many women’s emotions intensified when they discovered that despite all their hard work, they were still unable to breastfeed their babies as planned. A few women described reaching their “breaking point”, and their experience felt “like death”, “the worst day of [my] life” or “hell”. </p>
<p>One participant told us:</p>
<blockquote>
<p>I finally learned that ‘all women make enough milk’ was a lie. No amount of education or determination would make my breasts work. I felt deceived and let down by all my medical providers. How dare they have no answers for me when I desperately just wanted to feed my child naturally.</p>
</blockquote>
<p>Others told us how they learned to accept their situation. Some women said they were relieved their infant was “finally satisfied” when they began supplementing with formula. One resolved to:</p>
<blockquote>
<p>prioritise time with [my] baby over pumping for such little amounts.</p>
</blockquote>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-youre-feeding-with-formula-heres-what-you-can-do-to-promote-your-babys-healthy-growth-106165">If you're feeding with formula, here's what you can do to promote your baby's healthy growth</a>
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</p>
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<h2>Where to go for help</h2>
<p>If you are struggling with low milk supply, it can help to see a <a href="https://www.lcanz.org/resources/clients/how-do-i-access-a-lactation-consultant/">lactation consultant</a> for support and to determine the possible cause. </p>
<p>This will involve helping you try different strategies, such as optimising <a href="https://www.breastfeeding.asn.au/resources/attachment">positioning and attachment</a> during breastfeeding, or <a href="https://www.breastfeeding.asn.au/resources/increasing-supply">breastfeeding/expressing more frequently</a>. You may need to consider taking a medication, such as <a href="https://theconversation.com/domperidone-can-boost-breast-milk-supply-heres-what-you-need-know-88648">domperidone</a>, to see if your supply increases. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/domperidone-can-boost-breast-milk-supply-heres-what-you-need-know-88648">Domperidone can boost breast milk supply – here's what you need know</a>
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</em>
</p>
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<p>If these strategies do not help, there may be an underlying reason why you can’t make enough milk, such as insufficient glandular tissue (a confirmed inability to make a full supply due to breast hypoplasia).</p>
<p>Even if you have breast hypoplasia, you can still breastfeed by giving your baby extra milk (donor milk or formula) via a bottle or using a <a href="https://www.breastfeeding.asn.au/resources/supply-line">supplementer</a> (which involves delivering milk at the breast via a tube linked to a bottle). </p>
<h2>More resources</h2>
<p>The following websites offer further information and support:</p>
<ul>
<li><a href="https://www.breastfeeding.asn.au/">Australian Breastfeeding Association</a></li>
<li><a href="https://www.lcanz.org">Lactation Consultants of Australia and New Zealand</a></li>
<li><a href="https://www.thewomens.org.au/health-information/breastfeeding">Royal Women’s Hospital</a>, Melbourne</li>
<li><a href="https://www.facebook.com/groups/SupplyLineBreastfeedersSupportGroupAustralia/">Supply Line Breastfeeders Support Group of Australia</a> Facebook support group</li>
<li><a href="https://www.facebook.com/groups/IGTmamas/">IGT And Low Milk Supply Support Group</a> Facebook support group</li>
<li><a href="https://www.breastfeedingmed.com.au/">Breastfeeding Medicine Network Australia/New Zealand</a></li>
<li><a href="https://professoramybrown.co.uk/articles/f/supporting-breastfeeding-grief---a-collection-of-resources">Supporting breastfeeding grief</a> (a collection of resources).</li>
</ul>
<hr>
<p><em>Shannon Bennetts, a research fellow at La Trobe University, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/224858/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Feelings of failure, guilt, grief and despair are common, our study shows. But there is support.Renee Kam, PhD candidate and research officer, La Trobe UniversityLisa Amir, Professor in Breastfeeding Research, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230082024-02-21T03:45:57Z2024-02-21T03:45:57ZWhy do I keep getting urinary tract infections? And why are chronic UTIs so hard to treat?<figure><img src="https://images.theconversation.com/files/576612/original/file-20240219-26-qkb5eg.jpg?ixlib=rb-1.1.0&rect=209%2C473%2C7139%2C4429&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-tired-young-tattooed-business-woman-1703410366">BAZA Productions/Shutterstock</a></span></figcaption></figure><p>Dealing with chronic urinary tract infections (UTIs) means facing more than the occasional discomfort. It’s like being on a never ending battlefield against an unseen adversary, making simple daily activities a trial.</p>
<p>UTIs happen when bacteria sneak into the urinary system, causing pain and frequent trips to the bathroom. </p>
<p>Chronic UTIs take this to the next level, coming back repeatedly or never fully going away despite treatment. <a href="https://www.ncbi.nlm.nih.gov/books/NBK557479/">Chronic UTIs</a> are typically diagnosed when a person experiences two or more infections within six months or three or more within a year.</p>
<p>They can happen to anyone, but some are more prone due to their <a href="https://www.urologyhealth.org/urology-a-z/u/urinary-tract-infections-in-adults">body’s makeup or habits</a>. Women are more likely to get UTIs than men, due to their shorter urethra and hormonal changes during menopause that can decrease the protective lining of the urinary tract. Sexually active people are also at greater risk, as bacteria can be transferred around the area.</p>
<p>Up to <a href="https://www.urologyhealth.org/urology-a-z/u/urinary-tract-infections-in-adults#Related%20Resources">60% of women</a> will have at least one UTI in their lifetime. While effective treatments exist, <a href="https://www.health.harvard.edu/bladder-and-bowel/when-urinary-tract-infections-keep-coming-back#:%7E:text=Your%20urine%20might%20be%20cloudy,they%20take%20on%20your%20life.">about 25%</a> of women face recurrent infections within six months. Around <a href="https://sciendo.com/article/10.33073/pjm-2019-048?tab=article">20–30%</a> of UTIs don’t respond to standard antibiotic. The challenge of chronic UTIs lies in bacteria’s ability to shield themselves against treatments.</p>
<h2>Why are chronic UTIs so hard to treat?</h2>
<p>Once thought of as straightforward infections cured by antibiotics, we now know chronic UTIs are complex. The cunning nature of the bacteria responsible for the condition allows them to hide in bladder walls, out of antibiotics’ reach. </p>
<p>The bacteria form biofilms, a kind of protective barrier that makes them nearly impervious to standard antibiotic treatments. </p>
<p>This ability to evade treatment has led to a troubling <a href="https://theconversation.com/rising-antibiotic-resistance-in-utis-could-cost-australia-1-6-billion-a-year-by-2030-heres-how-to-curb-it-149543">increase in antibiotic resistance</a>, a global health concern that renders some of the conventional treatments ineffective.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
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<figure class="align-center ">
<img alt="Underpants hanging on a clothesline" src="https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576616/original/file-20240219-28-iawpj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some antibiotics no longer work against UTIs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/womens-underwear-hangs-on-clothesline-687500683">Michael Ebardt/Shutterstock</a></span>
</figcaption>
</figure>
<p>Antibiotics need to be advanced to keep up with evolving bacteria, in a similar way to the flu vaccine, which is updated annually to combat the latest strains of the flu virus. If we used the same flu vaccine year after year, its effectiveness would wane, just as overused antibiotics lose their power against bacteria that have adapted. </p>
<p>But fighting bacteria that resist antibiotics is much tougher than updating the flu vaccine. Bacteria change in ways that are harder to predict, making it more challenging to create new, effective antibiotics. It’s like a never-ending game where the bacteria are always one step ahead.</p>
<p>Treating chronic UTIs still relies heavily on antibiotics, but doctors are getting crafty, changing up medications or prescribing low doses over a longer time to outwit the bacteria. </p>
<p>Doctors are also placing a greater emphasis on thorough diagnostics to accurately identify chronic UTIs from the outset. By asking detailed questions about the duration and frequency of symptoms, health-care providers can better distinguish between isolated UTI episodes and chronic conditions. </p>
<p>The approach to initial treatment can significantly influence the likelihood of a UTI becoming chronic. Early, targeted therapy, based on the specific bacteria causing the infection and its antibiotic sensitivity, may reduce the risk of recurrence. </p>
<p>For post-menopausal women, <a href="https://link.springer.com/article/10.1007/s00192-020-04397-z">estrogen therapy</a> has shown promise in reducing the risk of recurrent UTIs. After menopause, the decrease in estrogen levels can lead to changes in the urinary tract that makes it more susceptible to infections. This treatment restores the balance of the vaginal and urinary tract environments, making it less likely for UTIs to occur.</p>
<p>Lifestyle changes, such as <a href="https://journals.lww.com/co-nephrolhypertens/FullText/2013/05001/Impact_of_fluid_intake_in_the_prevention_of.1.aspx">drinking more water</a> and practising good hygiene like washing hands with soap after going to the toilet and the recommended front-to-back wiping for women, also play a big role. </p>
<p>Some swear by cranberry juice or supplements, though researchers are still figuring out <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD001322.pub2/full">how effective these remedies truly are</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cranberry-juice-can-prevent-recurrent-utis-but-only-for-some-people-203926">Cranberry juice can prevent recurrent UTIs, but only for some people</a>
</strong>
</em>
</p>
<hr>
<h2>What treatments might we see in the future?</h2>
<p>Scientists are currently working on new treatments for chronic UTIs. One promising avenue is the development of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10052183/pdf/pathogens-12-00359.pdf">vaccines</a> aimed at preventing UTIs altogether, much like flu shots prepare our immune system to fend off the flu. </p>
<figure class="align-center ">
<img alt="Gynaecologist talks to patient" src="https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576617/original/file-20240219-16-qgkamv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Emerging treatments could help clear chronic UTIs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/gynecologist-talks-patient-during-medical-consultation-2298674535">guys_who_shoot/Shutterstock</a></span>
</figcaption>
</figure>
<p>Another new method being looked at is called <a href="https://link.springer.com/article/10.1007/s12223-019-00750-y">phage therapy</a>. It uses special viruses called bacteriophages that go after and kill only the bad bacteria causing UTIs, while leaving the good bacteria in our body alone. This way, it doesn’t make the bacteria resistant to treatment, which is a big plus. </p>
<p>Researchers are also exploring the potential of <a href="https://www.mdpi.com/2079-6382/12/1/167">probiotics</a>. Probiotics introduce beneficial bacteria into the urinary tract to out-compete harmful pathogens. These good bacteria work by occupying space and resources in the urinary tract, making it harder for harmful pathogens to establish themselves. </p>
<p>Probiotics can also produce substances that inhibit the growth of harmful bacteria and enhance the body’s immune response.</p>
<p>Chronic UTIs represent a stubborn challenge, but with a mix of current treatments and promising research, we’re getting closer to a day when chronic UTIs are a thing of the past.</p>
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Read more:
<a href="https://theconversation.com/phage-therapy-could-treat-some-drug-resistant-superbug-infections-but-comes-with-unique-challenges-207025">'Phage therapy' could treat some drug-resistant superbug infections, but comes with unique challenges</a>
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<img src="https://counter.theconversation.com/content/223008/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Iris Lim does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Chronic UTIs come back repeatedly or never fully go away despite treatment.Iris Lim, Assistant Professor, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2226342024-02-15T16:22:44Z2024-02-15T16:22:44ZJelqing: the latest in a long history of attempts to enlarge the male member<figure><img src="https://images.theconversation.com/files/575356/original/file-20240213-28-manb71.jpg?ixlib=rb-1.1.0&rect=15%2C15%2C5217%2C3467&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-caucasian-male-doctor-holding-measuring-1677475939">RealPeopleStudio/Shutterstock</a></span></figcaption></figure><p>Advice about a penis-enlargement method called jelqing (also “jelquing”) is being <a href="https://torontosun.com/news/world/penis-enlarging-trend-jelqing-explodes-online-can-actually-damage-your-manhood">widely shared</a> online. Posts advise that stretching a semi-erect penis could add up to an inch in length and girth by exploiting the body’s repair mechanisms. </p>
<p>Jelqing is just the latest in a long line of dubious penis enlargement techniques stretching (sorry) back millennia. </p>
<p>The ancient Greek method of <a href="https://www.cirp.org/library/history/hodges2/">lengthening the foreskin</a> with a <em>kynodesme</em> (dog leash) seems positively mild compared with ancient Indian methods. A Sanskrit text on medicine and surgery, called the <a href="https://link.springer.com/article/10.1007/s10508-008-9417-y">Sushruta Samhita</a>, advises rubbing the penis with bristled insects, then oils and then more bristled insects, which probably caused short-term enlargement due to infection or inflammation. </p>
<p>Then there are the men of the Brazilian Topinamá tribe who, in the 16th century, <a href="https://www.europeanurology.com/article/S0302-2838(08)00935-4/fulltext">allowed poisonous snakes</a> to bite their penises to increase size.</p>
<p>These days, pills are more likely to be proffered as a method of penis enlargement. They are far less painful than bristled insects and poisonous snakes, but equally as ineffective.</p>
<p>Most penis-enlargement pills are probably nothing more than vitamins. Although there are drugs, such as <a href="https://pubmed.ncbi.nlm.nih.gov/12414330/">Viagra</a>, that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1874251/">enhance the stiffness</a> of the penis, they treat <a href="https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/">erectile dysfunction</a>. </p>
<p>Penis pumps are also used for erectile dysfunction, but unlike some online claims, they <a href="https://pubmed.ncbi.nlm.nih.gov/16536772/">don’t lengthen</a> the penis. And persistent or incorrect use of these devices can lead to <a href="https://pubmed.ncbi.nlm.nih.gov/9586618/">bruising, bleeding or penile tissue death</a>.</p>
<p>Penis stretching devices require significant daily time investment over prolonged periods. There are small studies that show <a href="https://academic.oup.com/jsm/article-abstract/8/11/3188/6966755?redirectedFrom=fulltext&login=false">some improvement</a>, but these are over ten years old and haven’t led to larger studies or a revolution in treatments.</p>
<h2>Surgical interventions</h2>
<p>Penoplasty or phalloplasty surgeries are most effective for lengthening the penis. They are typically used for men with a decreased penis length following prostatectomy (removal of the prostate gland) or other conditions where the <a href="https://pubmed.ncbi.nlm.nih.gov/25733292/">length of the penis is affected</a> by structural factors, such as being <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4655706/">buried by skin</a>.</p>
<p>Fillers are increasing in popularity, particularly <a href="https://www.ncbi.nlm.nih.gov/books/NBK482440/">hyaluronic acid (HA) injections</a>. HA is popular because it is <a href="https://pubmed.ncbi.nlm.nih.gov/17466613/">doesn’t generate</a> an immune response. Injections with this substance increase penis volume and draw water in. Some <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8987147/">trials</a> have shown “significant enhancement of girth”. </p>
<p>However, HA is broken down over several months and requires top-ups. And incorrect administration can have <a href="https://www.sciencedirect.com/science/article/pii/S2050116121001252">serious side-effects</a>, from infection to preventing urination.</p>
<p>Surgery to cut the suspensory ligament anchoring the penis is the most widely accepted <a href="https://pubmed.ncbi.nlm.nih.gov/16473458/">surgical elongation method</a>. This surgery alters the angle that the <a href="https://pubmed.ncbi.nlm.nih.gov/9932326/">penis hangs from the body</a>, increasing the appearance of length. It can also be combined with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7436850/">liposuction to reduce pubic fat</a>, but these surgeries have <a href="https://pubmed.ncbi.nlm.nih.gov/16473458/">poor satisfaction rates</a>.</p>
<p>Fat transplantation from another region can <a href="https://pubmed.ncbi.nlm.nih.gov/22527585/">enhance girth</a>, with some success. However, about 30% of the <a href="https://pubmed.ncbi.nlm.nih.gov/16547638/">fat is lost</a> in the first two months, and scar tissue and infections are common, which can cause longer-term complications and, occasionally, even <a href="https://pubmed.ncbi.nlm.nih.gov/28749069/">death</a> when the fat breaks free and causes an embolism.</p>
<p>Implants, which come as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7719505/">inflatable</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10350748/">non-inflatable</a>, are used to treat erectile dysfunction. But they are also used cosmetically for penis enlargement. The results, though, are not great. There have been various reports of lack of <a href="https://karger.com/cur/article/13/2/94/102452/Clinical-Outcome-Patient-and-Partner-Satisfaction">satisfaction for the patient and their partner</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3126071/">infection</a>, damage to <a href="https://pubmed.ncbi.nlm.nih.gov/19453911/">internal organs</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8483239/">complications</a> such as <a href="https://pubmed.ncbi.nlm.nih.gov/31474579/">“floppy glans syndrome”</a> and, in some cases, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5715172/">death</a>.</p>
<p>A recent review concluded that <a href="https://bjui-journals.onlinelibrary.wiley.com/doi/10.1111/bju.15145">evidence</a> for supporting surgical procedures for penis enlargement is weak and the complications are <a href="https://www.sciencedirect.com/science/article/abs/pii/S2050052118301197">under-reported</a>.</p>
<h2>Not needed, in most cases</h2>
<p>Penis enlargement surgery is the <a href="https://www.nature.com/articles/s41598-019-41652-w">second</a> most sought after cosmetic surgery in men. But only men with a <a href="https://my.clevelandclinic.org/health/diseases/17955-micropenis">micropenis</a> may need treatment. </p>
<p>A micropenis, usually diagnosed at birth, is where the penis is 2.5 standard deviations less than the average stretched penis length (<a href="https://pubmed.ncbi.nlm.nih.gov/11805431/">2.3 to 2.5cm</a> depending on ethnicity). It is typically caused by a deficiency or imbalance of hormones such as <a href="https://www.jpeds.com/article/S0022-3476(99)70244-1/fulltext">testosterone</a> or <a href="https://pubmed.ncbi.nlm.nih.gov/8393754/">human chorionic gonadotropin</a> (hCG), or <a href="https://pubmed.ncbi.nlm.nih.gov/21535007/">genetics</a>. </p>
<p>Micropenis usually responds to <a href="https://pubmed.ncbi.nlm.nih.gov/37920173/">hormone therapy</a> in childhood, bringing size to the normal range.</p>
<p>Other than a man’s desire for a larger penis, is there any anatomical benefit? </p>
<p>The average male penis is between <a href="https://pubmed.ncbi.nlm.nih.gov/32666897/">5.1 and 5.5 inches</a> in length, with a recent study showing the latter value is a <a href="https://pubmed.ncbi.nlm.nih.gov/36792094/">24% increase on</a> three decades ago. The female vagina is on average <a href="https://pubmed.ncbi.nlm.nih.gov/16478763/">2.5</a> to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2893226/">3.8</a> inches deep, but <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC28302/">lengthens during sexual arousal</a> to accommodate a penis longer than this.</p>
<p>Research studies also show that <a href="https://bmcwomenshealth.biomedcentral.com/articles/10.1186/1472-6874-1-1">penile girth</a> is a more important characteristic than length for sexual satisfaction and there is no definite consensus on <a href="https://www.nature.com/articles/s41443-022-00636-7">length correlating with sexual satisfaction</a> – at least for heterosexual couples. The female genitalia have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3894744/">multiple erogenous structures</a> that can <a href="https://onlinelibrary.wiley.com/doi/10.1002/ca.22471">result in orgasm</a>, so penile length isn’t the key characteristic.</p>
<h2>A closer look at jelqing</h2>
<p>The <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/penis">penis</a> consists of three cylindrical structures. Two <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/corpus-cavernosum">corpus cavernosum</a> and a <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/corpus-spongiosum">corpus spongiosum</a>. The top two consist of numerous spaces that are surrounded by smooth muscle, which keeps most blood out of the spaces. </p>
<p>During an erection, the muscles relax allowing blood to flow in, filling these spaces, and enlarging penile volume. This enables penetration to occur. Among and around these structures are various bundles of connective tissue, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0022534717366302">primarily collagen</a>.</p>
<p>Jelqing appears to try and exploit the body’s repair mechanisms to heal microtears in the penile tissues, in the same way <a href="https://pubmed.ncbi.nlm.nih.gov/22522284/">microfractures</a> in bone and <a href="https://www.science.org/doi/10.1126/science.abe5620">microtears</a> in skeletal muscle heal bigger and stronger. </p>
<p>While the theory sounds good, smooth muscle cells in the penis don’t respond in the same way <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8075408/">skeletal muscle</a> does. <a href="https://pubmed.ncbi.nlm.nih.gov/2291488/">Smooth muscle increase in size</a> is usually due to disease or damage, and more importantly, when the penis is erect, the smooth muscle cells are actually relaxed and not working, so are not going to increase in size.</p>
<p>Jelqing also increases the risk of developing <a href="https://www.mayoclinic.org/diseases-conditions/peyronies-disease/symptoms-causes/syc-20353468">Peyronie disease</a> where scar tissue formation under the skin of the penis causes excessively curved erections and pain, particularly in the acute phase where the scar is still growing.</p>
<p>Scar tissues are <a href="https://www.ncbi.nlm.nih.gov/books/NBK554402/">weaker</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4352699/">not well aligned</a>, jeopardising normal function. Penile scar tissue <a href="https://pubmed.ncbi.nlm.nih.gov/11424963/">reduces penile blood flow</a> causing inability to get or maintain an erection. Developing this condition will also result in a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4893519/">shortening of the penis</a>.</p>
<p>If jelqing, or any other trend, was really that effective, we would have seen evidence of it in medical journals, and the sale of extra-large underwear would be making the headlines.</p><img src="https://counter.theconversation.com/content/222634/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Men will go to almost any length to increase their length. Mostly with disastrous consequences.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225532024-02-08T19:04:25Z2024-02-08T19:04:25ZErections: what we learned from mice could help with sexual health in men<figure><img src="https://images.theconversation.com/files/573745/original/file-20240206-24-zl3t51.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5463%2C3628&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pots-different-cacti-on-blue-background-2193845671">HenadziPechan/Shutterstock</a></span></figcaption></figure><p>Have you ever wondered how penile erection works but never dared to ask? Well, imagine a dry sponge in a condom. Now pour water on the sponge (that’s the blood flowing in). There you have it.</p>
<p>This penis “sponge” is scientifically termed corpora cavernosa. Erections depend on the influx and trapping of blood. Smooth muscle cells regulate the blood flow into the sponge and its subsequent firmness. In a <a href="https://doi.org/10.1126/science.ade8064">recent study</a>, my colleague and I delved into the role of penile fibroblasts, the most abundant cells in the human penis, about which little was previously known.</p>
<p>We discovered that penile fibroblasts help smooth muscle cells to relax. Using a technique to render cells light-sensitive enabled us to activate fibroblasts by shining blue light from outside onto the penises of mice. </p>
<p>We found that light-induced activation of fibroblasts relaxed smooth muscle cells and increased blood flow. The effectiveness of this relaxation-support depends on the number of fibroblasts. More fibroblasts led to easier relaxation and increased blood flow.</p>
<p>We also learned that the number of fibroblasts is not static and identified the signalling molecules regulating the number of fibroblasts in the penis. By deleting or over-expressing the relevant molecules, we could increase or decrease the number of fibroblasts and in response see the corresponding changes in penile blood flow. </p>
<p>But we quickly learned that too many fibroblasts has negative consequences. Mice with very high numbers of penile fibroblasts showed erections that lasted for several hours. In men, this corresponds to a painful pathological condition termed <a href="https://www.nhs.uk/conditions/priapism-painful-erections/">priapism</a>, which demands a visit to the hospital. </p>
<p>Can penile erection be trained? In humans, much of the “erectile training” occurs naturally during sleep, with men experiencing three to five erections a night, known as “nocturnal penile tumescence”. </p>
<p>To test the importance of training, we artificially changed the frequency of erections in mice by targeting the brain region responsible for initiating an erection. This technique allowed us to turn erections on and off by simply administrating a designer drug that specifically activated the responsible nerve cells in the mouse brain. </p>
<h2>More fibroblasts, more blood flow</h2>
<p>Surprisingly, we found that the number of penile fibroblasts changed in relation to the frequency of erections. The more frequent the erections, the more fibroblasts were present and the better the blood flow. This implies that it becomes easier to initiate and maintain an erection with increased erection frequency.</p>
<p>It is known that the unconscious “training” during sleep declines with increasing age. Ageing is one of the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5540144/">major risk factors</a> for erectile dysfunction in men. </p>
<p>Studying penises of aged mice, we found that they possessed a lower number of fibroblasts compared with young mice. When reducing the number of recurrent erections in young animals for a longer time, we found a decrease in the number of fibroblasts and lower penile blood flow. </p>
<p>One interpretation could be that reduced training negatively affects the number of fibroblasts and consequently, it becomes less efficient to initiate an erection. </p>
<p>While the spontaneous occurrence of erections during sleep is certainly convenient, our study does not suggest any differences between involuntary and actively evoked erections regarding the number of penile fibroblasts. So, an age-related decline of nocturnal penile tumescence could be a potential target for future treatment of erectile dysfunction or compensated for by actively achieving an erection. </p>
<p>Our research unveils a mechanism for controlling penile erections, opening the door for further exploration to understand and improve sexual health.</p><img src="https://counter.theconversation.com/content/222553/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christian Goeritz receives funding from: Bertil Hållsten Foundation, Knut and Alice Wallenberg Foundation, Swedish Research Council, Swedish Brain Foundation, Ming Wai Lau Centre for Reparative Medicine, Wings for Life Foundation, Swedish Cancer Foundation, the Government of Canada’s New Frontiers in Research Fund (NFRF), and the Strategic Network for Stem cells and Regenerative Medicine (STRATREGEN) at Karolinska Institutet.</span></em></p>Regular erections help to maintain the potency suggests a new study in mice.Christian Göritz, Associate Professor, Department of Cell and Molecular Biology, Karolinska InstitutetLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2216842024-01-28T13:55:15Z2024-01-28T13:55:15ZThe contraceptive pill also affects the brain and the regulation of emotions<figure><img src="https://images.theconversation.com/files/570657/original/file-20231221-19-oxth15.jpg?ixlib=rb-1.1.0&rect=2%2C0%2C988%2C667&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Like natural hormones, known as endogenous hormones, the artificial hormones contained in the pill, known as exogenous hormones, can have effects on the brain.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Oral contraceptives, also known as birth control pills, are <a href="https://doi.org/10.18356/1bd58a10-en">used by more than 150 million women worldwide</a>. Approximately one-third of teenagers in <a href="https://www150.statcan.gc.ca/n1/en/pub/82-003-x/2015010/article/14222-eng.pdf">North America</a> and <a href="https://doi.org/10.1001/jamapsychiatry.2016.2387">Europe</a> use them, making them the most prescribed drug for teenagers.</p>
<p>It is well known that oral contraceptives have the power to alter a woman’s menstrual cycle. What’s less well known is that they can also have an effect on the brain, particularly in the regions that are important for regulating emotions.</p>
<p>As a doctoral student and professor of psychology at UQAM, we were interested in the impact of oral contraceptives on the brain regions involved in emotional processes. We published our <a href="https://doi.org/10.3389/fendo.2023.1228504">results in the scientific journal Frontiers in Endocrinology</a>.</p>
<h2>How does the pill work?</h2>
<p>There are several methods of hormonal contraception, but the most common type in North America is the contraceptive pill, more specifically, <a href="https://doi.org/10.1016/j.yfrne.2022.101040">combined oral contraceptives</a> (COCs). These are made up of two artificial hormones that simulate one of the types of estrogen (generally ethinyl estradiol) and progesterone.</p>
<p>Like natural hormones, known as endogenous hormones, the artificial hormones contained in the pill, known as exogenous hormones, <a href="https://doi.org/10.1016/j.yfrne.2022.101040">have an effect on the brain</a>. They bind to receptors in different areas and signal the brain to reduce the production of endogenous sex hormones. It is this phenomenon that leads to the cessation of menstrual cycles, preventing ovulation.</p>
<p>In other words, while using COCs, users’ bodies and brains are not exposed to the fluctuations in sex hormones typically seen in women with a natural cycle.</p>
<h2>The pill’s effects on the brain: neuroscience to the rescue!</h2>
<p>When they start taking COCs, teenage girls and women are informed of their different side effects, mainly physical (nausea, headaches, weight changes, breast tenderness). However, the fact that sex hormones affect the brain, particularly in areas important for regulating emotions, is not generally discussed.</p>
<p>Studies have associated the use of COCs with <a href="https://doi.org/10.1016/j.psyneuen.2018.02.019">poorer ability to regulate emotions</a> and a <a href="https://doi.org/10.1001/jamapsychiatry.2016.2387">higher risk of developing psychopathologies</a>.</p>
<p>In addition, women are more likely than men to suffer from <a href="https://doi.org/10.1016/j.jpsychires.2011.03.006">anxiety and chronic stress disorders</a>. Given the widespread use of COCs, it is important to gain a better understanding of their effects on the anatomy of the brain regions that are responsible for emotional regulation.</p>
<p>We therefore conducted a study to examine the effects of COCs on the anatomy of brain regions involved in emotional processes. We were interested in the effects associated with their current use, but also in the possibility of lasting effects, i.e. whether COCs could affect brain anatomy even after women stopped taking them.</p>
<p>To do this, we recruited four profiles of healthy individuals: women currently using COCs, women who had used COCs in the past, women who had never used any method of hormonal contraception, and men.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="magnetic resonance imaging" src="https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567191/original/file-20231221-24-r2t5pd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Magnetic resonance imaging (MRI) is used to analyze the morphology of certain regions of the brain.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Using brain imaging, we found that only women currently using COCs had a slightly thinner ventromedial prefrontal cortex than men. This part of the brain is known to be essential for regulating emotions such as fear. The scientific literature shows that <a href="https://doi.org/10.1073/pnas.0502441102">the thicker this region is, the better the emotional regulation will be</a>.</p>
<p>COCs could therefore alter emotional regulation in women. Although we have not directly tested the link between brain morphology and mental health, our team is currently investigating other aspects of the brain and mental health, which will allow us to better understand our anatomical findings.</p>
<h2>An effect associated with the dose, but that doesn’t last</h2>
<p>We tried to better understand what could explain the effect using COCs on this region of the brain. We discovered that it was associated with the dose of ethinyl estradiol. In fact, among COC users, only those using a low-dose COC (10-25 micrograms) – not a higher dose (30-35 micrograms) – were associated with a thinner ventromedial prefrontal cortex.</p>
<p>It may seem surprising that a lower dose was associated with a cerebral effect…</p>
<p>Given that all COCs reduce concentrations of endogenous sex hormones, we propose that estrogen receptors in this brain region may be insufficiently activated when low levels of endogenous estrogen are combined with a low intake of exogenous estrogen (ethinyl estradiol).</p>
<p>Conversely, higher doses of ethinyl estradiol could help to achieve adequate binding to estrogen receptors in the prefrontal cortex, simulating moderate to high activity similar to that of women with a natural menstrual cycle.</p>
<p>It is important to note that this lower grey matter thickness was specific to current COC use: women who had used COCs in the past showed no thinning compared to men. Our study therefore supports the reversibility of the impact of COCs on cerebral anatomy, in particular on the thickness of the ventromedial prefrontal cortex.</p>
<p>In other words, the use of COCs could affect brain anatomy, but in a reversible way.</p>
<h2>And now?</h2>
<p>Although our research has no direct clinical orientation, it is helping to advance our understanding of the anatomical effects associated with the use of COCs.</p>
<p>We are not calling for women to stop using their COCs: adopting such discourse would be both too hasty and alarming.</p>
<p>It’s also important to remember that the effects reported in our study appear to be reversible.</p>
<p>Our aim is to promote basic and clinical research, but also to increase scientific interest in women’s health, an area that is still understudied.</p><img src="https://counter.theconversation.com/content/221684/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexandra Brouillard is a student member of the Research Centre of the Institut universitaire en santé mentale de Montréal. She holds a doctoral scholarship from the Canadian Institutes of Health Research.</span></em></p><p class="fine-print"><em><span>Marie-France Marin is a regular researcher at the Centre de recherche de l'Institut universitaire en santé mentale de Montréal, a professor in the Department of Psychology at the Université du Québec à Montréal and an associate professor in the Department of Psychiatry and Addictology at the Université de Montréal. She was supported by a salary grant from the Fonds de recherche du Québec - Santé (2018-2022) and currently holds a Canada Research Chair in Hormonal Modulation of Cognitive and Emotional Functions (2022-2027). The project discussed in the article is funded by the Canadian Institutes of Health Research and has received support from pilot project funds from the Research Centre of the Institut universitaire en santé mentale de Montréal and the Quebec Bioimaging Network.</span></em></p>Oral contraceptives modify the menstrual cycle. What’s less well known is that they also reach the brain, particularly the regions important for regulating emotions.Alexandra Brouillard, Doctorante en psychologie, Université du Québec à Montréal (UQAM)Marie-France Marin, Professor, Department of Psychology, Université du Québec à Montréal (UQAM)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2217802024-01-24T17:39:08Z2024-01-24T17:39:08ZHere’s what happens to your body during plane turbulence – and how to reduce the discomfort it causes<figure><img src="https://images.theconversation.com/files/570863/original/file-20240123-19-j98p69.jpg?ixlib=rb-1.1.0&rect=0%2C12%2C8179%2C5444&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-firmly-holds-mans-hand-during-1806710980">H Ko/Shutterstock</a></span></figcaption></figure><p>This week has seen another barrage of <a href="https://www.theguardian.com/uk-news/2024/jan/22/uk-weather-storm-jocelyn-to-follow-isha-with-more-strong-winds-and-heavy-rain">unsettled weather</a> sweep across the UK, with many flights delayed or cancelled. Some of those who were fortunate enough to take off found themselves arriving at destinations that weren’t on their boarding passes – such as passengers travelling from Stansted to Newquay who eventually diverted to <a href="https://uk.news.yahoo.com/storm-isha-creates-flight-diversion-142821278.html?">Malaga</a>.</p>
<p>One thing that was consistently described by passengers was that parts of the flights and the attempted landings were some of the most unnerving they’d ever experienced, due to turbulence.</p>
<p>Turbulence results from uneven air movement, which is <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL103814">increasing</a> in frequency. If you turn your hair dryer on at home and hold it still, the air moves at a constant rate, but once you begin drying your hair and moving the hairdryer around, the air movement becomes uneven, that is to say, turbulent.</p>
<p>Although turbulence may be unnerving and make you feel unwell, it is important to recognise that it is very common and typically <a href="https://pubmed.ncbi.nlm.nih.gov/18018437/">nothing to worry about</a> if you’re in your seat with your seatbelt fastened.</p>
<h2>How the body detects and responds to turbulence</h2>
<p>The body recognises itself within any environment. Its relationship with objects in terms of distance and direction is called <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780123750006003414">spatial orientation</a>. </p>
<p>When flying, this is typically moving forwards, ascending, some turns and a descent. However, turbulence disrupts this relationship and confuses the sensory information being received by the brain – it makes the body want to respond or recalibrate.</p>
<p>Our inner ears play a pivotal role in all this. It consists of complex apparatuses that undertake more than hearing. These include the cochlea, <a href="https://www.ncbi.nlm.nih.gov/books/NBK279394/">three semi-circular canals</a>, <a href="https://radiopaedia.org/articles/utricle-ear?lang=gb">the utricle</a> and <a href="https://radiopaedia.org/articles/saccule-ear-1?lang=gb">the saccule</a>. </p>
<p>The cochlea is responsible for hearing. It converts <a href="https://www.ncbi.nlm.nih.gov/books/NBK531483/">sound energy into electrical energy</a> that is then “heard” by the brain. The remaining structures are responsible for the balance and position of the head and body. The semi-circular canals are positioned in a vertical (side to side), horizontal and front-to-back plane, detecting movement in a nodding, shaking and touching ear-to-shoulder direction. </p>
<p>Attached to these canals are <a href="https://www.ncbi.nlm.nih.gov/books/NBK532978/">the utricle and saccule</a>, which can detect <a href="https://www.ncbi.nlm.nih.gov/books/NBK10792/">movement</a> and <a href="https://www.cell.com/current-biology/pdf/S0960-9822(05)00837-7.pdf">acceleration</a>. </p>
<p>All of these apparatuses use microscopic hair cells in a specialised fluid called <a href="https://www.ncbi.nlm.nih.gov/books/NBK531505/">endolymph</a> that flows with the head to create a sense of movement. When the plane encounters turbulence, this fluid moves around, but unpredictably. It takes <a href="https://www.ncbi.nlm.nih.gov/books/NBK518976/">about ten to 20 seconds</a> for the fluid to recalibrate its position, while the brain struggles to understand what is going on.</p>
<p>When the aircraft hits turbulence, the balance apparatus <a href="https://www.frontiersin.org/articles/10.3389/fneur.2023.949227/full">cannot distinguish</a> the movement of the plane from that of the head, so the brain interprets the aircraft movement as that of the head or body. But this doesn’t match the visual information being received, which causes sensory confusion.</p>
<p>The reason the inner ear causes so much confusion is because during flights you are devoid of your primary sensory tool relative to the external environment – your sight and the horizon. </p>
<p>Eighty per cent of <a href="https://www.ncbi.nlm.nih.gov/books/NBK518976/">spatial information</a> comes from your eyes during flight. However, you only have the seat in front of you or the cabin as a reference point, which means your inner ear becomes the dominant sensory message to the brain during turbulence and disrupts the <a href="https://www.ncbi.nlm.nih.gov/books/NBK545297/">“vestibulo-ocular reflex”</a>. This reflex keeps your vision <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4130651/">aligned</a> with your balance or expected position. </p>
<p>Vision is the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777262/">most valued</a> of the senses and one-third of the brain is attributed to its function, reinforcing its importance in spatial orientation.</p>
<p>This sensory mixed messaging often results in things like dizziness and sweating as well as gastrointestinal symptoms, such as <a href="https://www.airmedicaljournal.com/article/S1067-991X(02)70038-2/fulltext">nausea and vomiting</a>. </p>
<p>Motion sickness can be triggered by turbulence and although research into specific airsickness is limited, other modes that induce motion sickness suggest that <a href="https://pubmed.ncbi.nlm.nih.gov/16018346/">women</a> are <a href="https://pubmed.ncbi.nlm.nih.gov/26466829/">more susceptible</a> than men, particularly in the <a href="https://pubmed.ncbi.nlm.nih.gov/16235881/">early stages</a> of the menstrual cycle. </p>
<p>The turbulence also causes an increase in your heart rate, which is already higher than normal when flying because of a <a href="https://pubmed.ncbi.nlm.nih.gov/15819766/">decrease in oxygen saturation</a>.</p>
<h2>What about the pilots?</h2>
<p>Commercial pilots accrue thousands of hours at the controls, they are subject to the same forces as the passengers. </p>
<p>Over time, they can <a href="https://academic.oup.com/milmed/article/180/11/1135/4160573">adapt to these forces</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/15828634/">experiences</a>, but they also have a couple of additional resources that most passengers don’t. </p>
<p>They have the view out of the cockpit windows, so have a horizon to use as a reference point and can see what lies immediately ahead. </p>
<p>If it is cloudy or visibility is low, their instruments provide additional visual <a href="https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/phak/19_phak_ch17.pdf">reference</a> to the position of the aircraft. This doesn’t mean they are immune to the effects of turbulence, with some studies reporting up to <a href="https://pubmed.ncbi.nlm.nih.gov/26540704/">71% of trainee pilots</a> reporting episodes of airsickness.</p>
<h2>How to reduce the discomfort</h2>
<p>A window seat can help, or even looking out the window. This gives the brain some sensory information through visual pathways, helping calm the brain in response to the vestibular information it is receiving.</p>
<p>If you can get one, a seat towards the front or over the wing reduces the effects of turbulence.</p>
<p>Deep or rhythmical breathing can help reduce motion sickness induced by turbulence. Focusing on your breathing <a href="https://pubmed.ncbi.nlm.nih.gov/25945662/">calms the nervous system</a>.</p>
<p>Don’t reach for the alcohol. While you may feel it calms your nerves, if you hit turbulence it’s going to interfere with your <a href="https://pubmed.ncbi.nlm.nih.gov/7610847/">visual and auditory processing</a> and increase the likelihood of vomiting.</p>
<p>If you suffer from motion sickness and are worried about turbulence while flying, then there are also <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6241144/">drugs that can help</a>, including certain <a href="https://www.nhs.uk/medicines/cinnarizine/about-cinnarizine/">antihistamines</a>. </p>
<p>Finally, it’s important to remember that although turbulence can be unpleasant, aircraft are designed to withstand the forces it generates and many passengers, even frequent fliers, will rarely encounter the most severe categories of turbulence because pilots actively plan routes to avoid it.</p><img src="https://counter.theconversation.com/content/221780/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An anatomist explains why turbulence on flights makes us feel so ill and disoriented.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189982024-01-24T13:29:56Z2024-01-24T13:29:56ZPictures have been teaching doctors medicine for centuries − a medical illustrator explains how<figure><img src="https://images.theconversation.com/files/565002/original/file-20231211-30-bxjrr5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1524%2C1770&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artists reveal what cannot be seen.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/internetarchivebookimages/17573010234">Henry Gray, Anthony Edwward Spitzka/Internet Archive via Flickr</a></span></figcaption></figure><p>“Medical illustrators draw what can’t be seen, watch what’s never been done, and tell thousands about it without saying a word.”</p>
<p>For decades, this slogan <a href="https://web.archive.org/web/20070203080223/http://www.ami.org/ECOMAMI/timssnet/common/tnt_frontpage.cfm">appeared on the website</a> and printed materials of the <a href="https://ami.org">Association of Medical Illustrators</a>. Although the association no longer uses this tag line, it’s still an accurate description of the profession.</p>
<p>As a <a href="https://www.rit.edu/directory/japfaa-james-perkins">practicing medical illustrator</a> for over 30 years, I draw what can’t be seen and watch what’s never been done on a daily basis. And I teach my students to do the same. </p>
<p>But what exactly does all of that mean, and how does it improve medicine?</p>
<h2>Tell thousands about it without saying a word</h2>
<p>You may have heard the adage, “A picture is worth a thousand words.” In that same vein, medical illustrators use pictures to teach complex scientific concepts. As the famed medical illustrator <a href="https://www.netterimages.com/artist-frank-h-netter.html">Frank H. Netter</a> once said, “(Pictures) eliminate the need for the lecturer or the author to translate what he has in his mind into words and for the listener or the student to translate those words back into a mental image.”</p>
<p>The use of illustrations to communicate medical information has a long history, dating back at least to <a href="https://doi.org/10.1002/(SICI)1098-2353(1999)12:2%3C120::AID-CA7%3E3.0.CO;2-V">ancient Egypt</a> and flourishing in the Renaissance. The work of 16th century anatomists <a href="https://doi.org/10.3389%2Ffnana.2019.00011">Giacomo Berengario da Carpi</a> and <a href="https://doi.org/10.5339%2Fgcsp.2015.66">Andreas Vesalius</a> set a precedent for the use of detailed illustrations to teach anatomy, a practice that continues to this day.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration depicting the musculature of the human body with text identifying each component" src="https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=820&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=820&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=820&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1031&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1031&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564995/original/file-20231211-19-hqv8w6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1031&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is a page from Andreas Vesalius’ ‘Suorum de humani corporis fabrica librorum epitome.’</span>
<span class="attribution"><a class="source" href="https://wellcomecollection.org/works/g6b6smge/images?id=w5d9ed8q">Andreas Vesalius/Wellcome Collection</a></span>
</figcaption>
</figure>
<p>The proliferation of illustrated anatomy atlases in the Renaissance coincided with the widespread acceptance of <a href="https://doi.org/10.5115%2Facb.2015.48.3.153">cadaver dissection</a>. The earliest known human dissections were performed in the third century BCE. The practice was prohibited throughout the Middle Ages but became common again in the 13th and 14th centuries. </p>
<p>By the 1500s, dissections, usually of executed criminals, had become public spectacles. The demand for bodies eventually outstripped the supply of executed convicts, leading to the unscrupulous practices of grave robbing and even murder.</p>
<p>In addition to depicting the location and features of an object such as an organ, illustrations proved essential in describing events happening over time, such as the progression of a disease or the steps in a surgical procedure. Generations of surgeons learned new procedures from meticulously illustrated surgical atlases. An early example of physiology illustration, William Harvey’s classic 17th century work on the circulation of blood, “<a href="https://library.si.edu/digital-library/book/exercitatioanat00harv">Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus</a>,” depicts the direction of blood flow through the veins of the forearm.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration showing an arm gripping a pole with a tourniquet wrapped around the elbow." src="https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564993/original/file-20231211-17-ppw1y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This image from William Harvey’s ‘Exercitatio’ depicts the direction of normal blood circulation.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:William_Harvey_(1578-1657)_Venenbild.jpg">William Harvey/Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>Nowadays, surgeons can practice a procedure hundreds of times <a href="https://theconversation.com/why-virtual-reality-wont-replace-cadavers-in-medical-school-67448">in virtual reality</a> before trying it on a real patient. Modern physiology and pathology texts include countless illustrations of the body, not just at the anatomical level but also the cellular and molecular. So valuable are these depictions of complex pathways and interactions that many science journals now require papers to include a <a href="https://doi.org/10.7759/cureus.45762">graphical abstract</a>, a single illustration that summarizes the content of each paper.</p>
<h2>Draw what can’t be seen</h2>
<p>Medical illustrators employ special tools and training to visualize things that are normally hidden from the naked eye. </p>
<p>All professionally trained medical illustrators <a href="https://ami.org/medical-illustration/enter-the-profession/careers">study human gross anatomy</a>, including dissecting a human cadaver, in order to visualize the internal structures of the body. When a cadaver isn’t readily available to serve as reference for an illustration, illustrators use <a href="https://doi.org/10.1148/rg.2018170088">medical imaging</a>, such as CT and MRI scans, and reconstruct the body in three dimensions.</p>
<p>At the cellular level, medical illustrators must understand how to use <a href="https://theconversation.com/seeing-what-the-naked-eye-cant-4-essential-reads-on-how-scientists-bring-the-microscopic-world-into-plain-sight-211666">microscopy techniques</a> in order to find references for accurate depictions of cellular structures. </p>
<p>Objects at the smallest scale – atoms and many molecules – are smaller than the wavelength of visible light. This means they are <a href="https://www.purdue.edu/uns/html4ever/1998/9804.Crystallography.html">below the theoretical limit</a> of what can be seen, even with the most powerful light microscope. So researchers experimentally determine the structures of molecules using techniques like <a href="https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Instrumentation_and_Analysis/Diffraction_Scattering_Techniques/X-ray_Crystallography">X-ray crystallography</a> and <a href="https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Spectroscopy/Nuclear_Magnetic_Resonance_Spectroscopy">nuclear magnetic resonance spectroscopy</a> instead. These techniques use X-rays or radio waves, respectively, to determine how atoms are arranged.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="CDC illustration of COVID-19 virus" src="https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564990/original/file-20231211-17-o2rq6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This illustration, created by the Centers for Disease Control and Prevention, depicts the notorious spiked structure of the virus that causes COVID-19.</span>
<span class="attribution"><a class="source" href="https://phil.cdc.gov/Details.aspx?pid=23311">Alissa Eckert, MSMI; Dan Higgins, MAMS via CDC</a></span>
</figcaption>
</figure>
<p>Medical illustrators learn to locate and retrieve data on the structure of molecules from sites like the <a href="https://www.rcsb.org">RCSB Protein Databank</a>. They also use a host of visualization applications and software plug-ins to render these structures in 3D.</p>
<p>Medical illustrators Alissa Eckert and Dan Higgins at the U.S. Centers for Disease Control and Prevention used these techniques to create the famous <a href="https://phil.cdc.gov/Details.aspx?pid=23311">red-spiked coronavirus image</a> that went viral during the pandemic.</p>
<h2>Watch what’s never been done</h2>
<p>Obviously, you can’t really watch something that has never been done. But medical illustrators can help conceptualize new processes and techniques before they become a reality. </p>
<p>For example, they might illustrate how an experimental drug may theoretically work before it enters testing. Similarly, illustrations can be critically important in <a href="https://doi.org/10.7759%2Fcureus.40841">pre-surgical planning</a>, especially in complex cases.</p>
<p>My favorite example of the role of medical illustration in surgery is the separation of conjoined twins Abbigail and Isabelle Carlsen at the Mayo Clinic in 2006. Working from <a href="https://dl.acm.org/doi/10.1145/1401032.1401099">nearly 6,000 radiographic images</a>, the clinic’s medical illustrators produced five detailed illustrations of the twins’ anatomy. They even generated 3D-printed models of important structures, notably their shared liver. </p>
<p>The illustrations were critical in training a team of 70 surgeons, nurses and technicians involved in the case. They also served as a road map for the ultimately successful surgery, hung up on the walls of the operating theater during the procedure.</p>
<h2>Road to becoming a medical illustrator</h2>
<p>In order to draw what can’t be seen and watch what’s never been done, medical illustrators require specialized training. Most medical illustrators in North America are trained at <a href="https://ami.org/medical-illustration/enter-the-profession/education/graduate-programs">master’s programs</a> accredited by the Association of Medical Illustrators in conjunction with the Commission on Accreditation of Allied Health Education Programs. </p>
<p>Since the profession requires a strong understanding of the biomedical sciences, students accepted into these programs must have a <a href="https://ami.org/medical-illustration/enter-the-profession/education">strong science background</a> along with a portfolio demonstrating outstanding drawing skills. Students often have a double major in biology and art or a major in one area and minor in the other. </p>
<p>Once in the program, their science training continues with human gross anatomy and some combination of courses in neuroanatomy, embryology, histology, cell biology, pathology and immunology. Specialized courses in surgical observation and cellular and molecular visualization also include significant science content. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/7AEDUteTegw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Scientific illustrator Val Altounian of the journal Science walks viewers through her process.</span></figcaption>
</figure>
<p>Students receive extensive training in <a href="https://ami.org/medical-illustration/enter-the-profession/education">computer graphics</a>, including 2D digital illustration and animation, 3D computer modeling and animation, interactive media, virtual and augmented reality and educational game and mobile app design. Courses also emphasize the principles of design, including the use of color, layout and motion to create effective visuals. </p>
<p>Medical illustrators learn to <a href="https://www.wired.com/story/in-a-pandemic-medical-illustrators-made-science-accessible/">consider the educational level of their audience</a>, since their work may be used to educate patients – even kids – in addition to medical professionals. Illustrations made for a child recently diagnosed with leukemia would be very different from those aimed at the oncologist treating the disease.</p>
<p>After entering the workforce, many medical illustrators pursue optional board certification to become a <a href="https://www.ami.org/medical-illustration/board-certification">certified medical illustrator</a>, which recognizes professional competency and encourages continued learning. Continued certification requires 35 hours of continuing education every five years in the biomedical sciences, artistic techniques and business practices. </p>
<p>All of this education and training is essential to ensure that medical illustrators communicate complex scientific information with accuracy and clarity. I like to think of medical illustrators as teachers – they instruct with pictures.</p><img src="https://counter.theconversation.com/content/218998/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James A. Perkins is a Professional Member of the Association of Medical Illustrators. </span></em></p>From body snatching to Photoshop and virtual reality, the techniques of medical illustration have evolved. But its essential role in showing clinicians how to care for the body continues today.James A. Perkins, Distinguished Professor of Medical Illustration, Rochester Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2135112023-12-27T09:11:18Z2023-12-27T09:11:18ZFascia: the most neglected part of our body is finally starting to receive attention<figure><img src="https://images.theconversation.com/files/551706/original/file-20231003-16-lps8ae.jpg?ixlib=rb-1.1.0&rect=13%2C13%2C4587%2C3049&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/human-anatomy-exhibition-by-gunther-von-1275690106">Photo Inspiration/Shutterstock</a></span></figcaption></figure><p>We are constantly reminded about how exercise benefits our <a href="https://ijbnpa.biomedcentral.com/articles/10.1186/s12966-020-01040-4">bone</a> and <a href="https://www.nia.nih.gov/news/how-can-strength-training-build-healthier-bodies-we-age#muscle">muscle</a> health or <a href="https://pubmed.ncbi.nlm.nih.gov/37497435/">reduces fat</a>. However, there is also a growing interest in one element of our anatomy that is often overlooked: our <a href="https://my.clevelandclinic.org/health/body/23251-fascia">fascia</a>. </p>
<p>Fascia is a thin casing of connective tissue, mainly made of <a href="https://www.ncbi.nlm.nih.gov/books/NBK507709/">collagen</a> – a rope-like structure that provides strength and protection to many areas of the body. It surrounds and holds every organ, blood vessel, bone, nerve fibre and muscle in place. And scientists increasingly recognise its importance in muscle and bone health.</p>
<p>It is hard to see fascia in the body, but you can get a sense of what it looks like if you look at a steak. It is the thin white streaks on the surface or between layers of the meat.</p>
<p>Fascia provides general and special functions in the body, and is arranged in several ways. The closest to the surface is the <a href="https://pubmed.ncbi.nlm.nih.gov/17061033/">superficial fascia</a>, which is underneath the skin between layers of fat. Then we have the deep fascia that covers the muscles, bones and blood vessels.</p>
<p>The link between fascia, muscle and bone health and function is reinforced by recent studies that show the important role fascia has in helping <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6455047/">the muscles work</a>, by assisting the contraction of the muscle cells to <a href="https://link.springer.com/article/10.1007/s11916-014-0441-4">generate force</a> and affecting muscle stiffness. </p>
<p>Each <a href="https://training.seer.cancer.gov/anatomy/muscular/structure.html">muscle is wrapped in fascia</a>. These layers are important as they enable muscles that sit next to, or on top of, each other to move freely without affecting each other’s functions.</p>
<p>Fascia also assists in the transition of force through the musculoskeletal system. An example of this is our ankle, where the achilles tendon <a href="https://pubmed.ncbi.nlm.nih.gov/10710257/">transfers force</a> into the plantar fascia. This sees forces moving vertically down through the achilles and then transferred horizontally into the bottom of the foot - the plantar fascia – when moving. </p>
<p>Similar force transition is seen from muscles in the chest <a href="https://onlinelibrary.wiley.com/doi/10.1002/ca.23424">running down through to</a> groups of muscles in the forearm. There are similar <a href="https://pubmed.ncbi.nlm.nih.gov/26281953/">fascia connective chains</a> through other areas of the body. </p>
<h2>When fascia gets damaged</h2>
<p>When fascia doesn’t function properly, such as after injury, the layers become less able to facilitate movement over each other or help transfer force. Injury to fascia takes a long time to <a href="https://link.springer.com/article/10.1007/s11916-014-0441-4">repair</a>, probably because it possesses similar cells to tendons (fibroblasts), and has a <a href="https://www.nature.com/articles/s41598-023-33479-3">limited</a> blood supply. </p>
<p>Recently, fascia, particularly the layers close to the surface, have been shown to have <a href="https://www.frontiersin.org/articles/10.3389/fnana.2022.981426/full">the second-highest number of nerves</a> after the skin. The fascial linings of muscles have also been linked to <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1002/jor.24665">pain</a> from surgery to musculoskeletal injuries from sports, exercise and ageing. Up to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1026905/">30% of people</a> with musculoskeletal pain may have fascial involvement or <a href="https://pubmed.ncbi.nlm.nih.gov/27475508/">fascia may be the cause</a>.</p>
<p>A type of massage called <a href="https://pubmed.ncbi.nlm.nih.gov/19118795/">fascial manipulation</a>, developed by Italian physiotherapist Luigi Stecco in the 1980s, has been shown to improve the pain from patellar tendinopathy (pain in the tendon below the kneecap), both in the short and long term. </p>
<p>Fascial manipulation has also shown positive results in treating <a href="https://www.sciencedirect.com/science/article/pii/S1360859208000752">chronic shoulder pain</a>. </p>
<p>One of the growing trends for helping with musculoskeletal injuries is Kinesio tape, which is often used in professional sports, although evidence for its effectiveness is mixed. It is also being used to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4491400/">complement the function</a> of the fascia, and is used to treat chronic lower back pain where <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0250686">fascial involvement</a> is a factor. </p>
<figure class="align-center ">
<img alt="A runner with Kinesio tape on his legs." src="https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A runner with Kinesio tape on his legs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/male-athlete-tape-on-his-knees-472723348">Real Sports Photos/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Fascia in disease</h2>
<p>Aside from getting damaged, fascia can also provide paths that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2823166/">infections can travel along</a>, <a href="https://www.sciencedirect.com/science/article/pii/S1743919112007650">within muscles</a>. </p>
<p>The spaces between fascial layers are usually closed (think of cling film being folded over), but when an infection occurs, germs can spread between these layers. This is a particular problem <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6716171/">in the neck</a>, where there are <a href="https://www.ncbi.nlm.nih.gov/books/NBK513262/">several layers of fascia</a> for infections to travel along. </p>
<p>In severe cases, surgery is often needed to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4286984/">remove the dead tissue</a> and save the healthy remaining tissue.</p>
<p>One of the primary examples of fascia functioning in health, and the challenges its dysfunction can bring, is seen in the common complaint <a href="https://www.nhs.uk/conditions/plantar-fasciitis/">plantar fasciitis</a>, which causes pain on around the heel and arch of the foot. </p>
<p>This incredibly common ailment affects <a href="https://cks.nice.org.uk/topics/plantar-fasciitis/background-information/prevalence/">5-7%</a> of people, rising to <a href="https://bjsm.bmj.com/content/52/5/322.long">22% in athletes</a>. It is recognised as an overuse injury, causing the thickening of the fascial bands on the soles of the feet that help give the arch support. </p>
<p>Fascia can also be implicated in more serious health conditions, such as <a href="https://www.cdc.gov/groupastrep/diseases-public/necrotizing-fasciitis.html">necrotising fasciitis</a>. This is a rare but serious bacterial condition that can spread through the body quickly and cause death. </p>
<p>The condition is almost always caused by bacteria, specifically group A <a href="https://pubmed.ncbi.nlm.nih.gov/23795951/">Streptococcus</a> or <a href="https://www.frontiersin.org/articles/10.3389/fgene.2022.964358/full"><em>Staphylococcus aureus</em></a>. The initial infection comes from a cut or scratch, and then the bacteria travel along the fascia to other areas away from the initial site of access and multiply in the ideal environment afforded by the warm recesses of the body.</p>
<h2>We can see it better now</h2>
<p>One reason fascia has been overlooked in health and disease is because it was difficult to see using current imaging technology. More recently, though, MRI and ultrasound imaging have been shown to be beneficial in visualising fascia, particularly in musculoskeletal conditions such as <a href="https://bmcmedimaging.biomedcentral.com/articles/10.1186/s12880-019-0361-1">plantar fasciitis</a>, and pathological changes in the fascia of the <a href="https://www.mdpi.com/2075-4418/13/15/2601">shoulder</a> and <a href="https://www.sciencedirect.com/science/article/pii/S1360859221000395">neck</a>.</p>
<p>With the growing interest in fascia and the growing understanding of its contribution to musculoskeletal health, it’s sensible to suggest that we look after it in the same way we do with the rest of the musculoskeletal system - by using it. Simple techniques like foam rollers and stretching are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4637917/">beneficial in increasing mobility</a>, but there is still much to learn about our fascia and the role it plays in our day-to-day health. </p>
<p><em>Clarification. The sentence: “One of the growing trends for helping with musculoskeletal injuries is Kinesio tape, which is often used in professional sports” has been amended to make it clear that evidence for the tape’s effectiveness is mixed.</em></p><img src="https://counter.theconversation.com/content/213511/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The much understudied fascia – our body’s own version of Spanx – is now coming under increasing scientific scrutiny.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2195142023-12-27T09:09:55Z2023-12-27T09:09:55ZMagnets, mating and metallic objects – cautionary tales from the MRI scanner<figure><img src="https://images.theconversation.com/files/567081/original/file-20231221-25-z03ybo.jpg?ixlib=rb-1.1.0&rect=14%2C21%2C4760%2C3156&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">What's the worst that can happen?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/female-patient-undergoing-mri-magnetic-resonance-1006650823">KaliAntye/Shutterstock</a></span></figcaption></figure><p>A 57-year-old <a href="https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=17404241&pc=LNH&device_sequence_no=1">woman</a> from Wisconsin recently sustained a rather unfortunate injury to her buttock. She had attended the hospital for an MRI (magnetic resonance imaging) scan and had entered the machine with a concealed firearm. The machine’s powerful magnet caused the gun to discharge.</p>
<p>This isn’t the first time in 2023 that a firearm injury has been sustained in an MRI scanner. In February a <a href="https://www.independent.co.uk/news/world/americas/brazil-lawyer-death-mri-gun-b2279514.html">lawyer in Brazil</a> died after the gun tucked in his waistband discharged into his abdomen.</p>
<p>MRI has a long history, in one form or another, dating back to the <a href="https://www.nobelprize.org/prizes/physics/1944/rabi/biographical/">1930s</a>. Many years of studying and adapting led to the first patient scan occurring in <a href="https://www.smithsonianmag.com/science-nature/the-indomitable-mri-29126670/">1977</a>. </p>
<p>Around <a href="https://www.gehealthcare.com/insights/article/committing-to-sustainability-in-mri#_ftn7">95 million MRI scans</a> are performed every year. It is an <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036752/">effective and valuable</a> diagnostic tool, which is incredibly safe for patients (when patients follow guidelines) giving excellent tissue resolution in diagnostic images and not exposing the recipient to any harmful ionising radiation. </p>
<p>While it is safe, there are some concerns from patients about the noise the machines make (earplugs are offered), which can reach <a href="https://hearing.health.mil/Prevention/Causes-of-Injury/High-Decibel-Levels">100 decibels</a>. And some people with <a href="https://radiology.pitt.edu/sites/rad_docs/mrrc-docs/ContraindicationsMRI.pdf">claustrophobia</a> struggle to tolerate long periods in the machine.</p>
<p>MRI works by applying <a href="https://www.nibib.nih.gov/science-education/science-topics/magnetic-resonance-imaging-mri">powerful magnetic fields</a> to whatever is being imaged. These magnets produce a magnetic field that is <a href="https://www.gehealthcare.com/insights/article/what-does-tesla-mean-for-an-mri-and-its-magnet">30,000 stronger</a> than that of the Earth. </p>
<p>The <a href="https://www.space.com/protons-facts-discovery-charge-mass">protons</a> (subatomic particles) that make up every element in the body (and universe) are excited, causing them to move out of their normal relaxed state. When the magnet is turned off, the sensors of the machine detect the released energy from the protons as they return to their resting state. This enables scientists to tell the difference between types of tissue and whether they are <a href="https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/magnetic-resonance-imaging-mri-of-the-spine-and-brain">healthy</a>.</p>
<h2>Strong magnets</h2>
<p>One of the biggest risks with MRI comes from the incredibly strong magnets that are used because they are not selective in the objects they act on. They can pull metallic objects into the field from anywhere in the room, as seen with the previously mentioned firearm incidents, or do damage by heating the items while in or against the body, causing burning.</p>
<p>For this reason, there are strict guidelines for MRI scans, with patients having to undergo a pre-scan questionnaire relating to medical history and potential metallic objects to prevent injury or death.</p>
<p>People with pacemakers or other implanted electronic devices used to be particularly at risk of harm. However, <a href="https://radiology.ucsf.edu/patient-care/patient-safety/mri">special procedures</a> have been put in place to support people with these implanted devices being scanned. Also, newer models tend not to contain <a href="https://www.sciencedirect.com/science/article/pii/S0735109715039364">ferrous metals</a> – that is, metals that can be attracted by magnets because they contain iron.</p>
<p>People with foreign metallic bodies located within them are also at high risk. A 65-year-old man with schizophrenia who had ingested metal sockets and a hinge pin had his <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8373193/#b3-cpcem-5-362">stomach ripped open</a> while undergoing an MRI.</p>
<p>Similarly, a child suffered bowel perforation during an MRI after ingesting 11 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3468355/">small spherical magnets</a>.</p>
<p>Another risk is the formation of a so-called “tissue loop” where one piece of the body is in contact with another creating a loop that heats the tissue to burning point. Examples include parts of the upper thigh <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7550826/">contacting each other</a>, <a href="https://austinpublishinggroup.com/hematology/fulltext/hematology-v2-id1053.php">hands coming together</a> and other points where one piece of skin is in <a href="https://academic.oup.com/jbcr/article/34/2/e110/4565904?login=true">contact with another</a>. These are uncommon but are mitigated by getting people to lie in certain positions to ensure a safe scan.</p>
<h2>Outside the machine can be dangerous too</h2>
<p>Hospitals and clinics have measures in place to limit the proximity of metallic objects to the MRI suite – but, on rare occasions, these aren’t followed.</p>
<p>In 2018, an Indian man <a href="https://www.theguardian.com/world/2018/jan/30/mri-scanner-india-death">was killed</a> when an oxygen cylinder he was carrying was pulled into the MRI machine, causing it to rupture and kill him. </p>
<p>Similarly, in 2021, a South Korean man died when an oxygen cylinder in the MRI room crushed his skull after the magnet pulled it into the machine he was being scanned in.</p>
<p>One of the greatest unknown risks comes from bits of metal lodged in the eye. This is typically a problem among <a href="https://pubmed.ncbi.nlm.nih.gov/33230610/">manual labourers</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/30037644/">military veterans</a>, where hammering, chiselling, drilling or shooting or explosions may have caused microscopic metal shards to become lodged – often unknowingly – in the person’s eye. </p>
<p>These small pieces of metal can become dislodged or twist to align with the magnetic field during MRI scanning, leading to <a href="https://pubmed.ncbi.nlm.nih.gov/25523608/">bleeding in the eye</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5972104/">excruciating pain</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8332697/pdf/3082156.pdf">blindness</a>.</p>
<h2>Benefits far outweigh the risks</h2>
<p>Despite the above stories, MRI is a revolutionary diagnostic machine that has benefits that far outweigh the risks. </p>
<p>Further modifications of MRI, such as fMRI (functional MRI), let doctors and researchers look at brain activity and observe how diseases, such as Alzheimer’s, are <a href="https://www.mdpi.com/1424-8220/23/14/6330">progressing</a>. They are also helping researchers discover <a href="https://pubmed.ncbi.nlm.nih.gov/21635967/">new drugs</a> and study anatomy – including <a href="https://www.bmj.com/content/319/7225/1596">during sex</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5675825/">orgasm</a>. </p>
<figure class="align-center ">
<img alt="MRI image of anatomy of sexual intercourse." src="https://images.theconversation.com/files/567112/original/file-20231221-17-9dj575.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567112/original/file-20231221-17-9dj575.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=475&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567112/original/file-20231221-17-9dj575.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=475&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567112/original/file-20231221-17-9dj575.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=475&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567112/original/file-20231221-17-9dj575.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=597&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567112/original/file-20231221-17-9dj575.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=597&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567112/original/file-20231221-17-9dj575.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=597&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">MRI has allowed some historical misconceptions about human anatomy during intercourse to be righted.</span>
<span class="attribution"><a class="source" href="https://www.bmj.com/content/bmj/319/7225/1596/F2.large.jpg">R L Dickinson and drawn by R S Kendall</a></span>
</figcaption>
</figure>
<p>These revolutionary machines are extremely useful and are entirely safe when used correctly. So next time you have an MRI scan, when clinical staff ask what seems like innocent and straightforward questions, answer honestly. And tell them about anything you think may be relevant, no matter how trivial, just to be on the safe side.</p><img src="https://counter.theconversation.com/content/219514/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>People have been shot with their own guns inside these giant magnets.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2169802023-12-21T21:37:49Z2023-12-21T21:37:49ZThe Douglas-Bell Canada Brain Bank: a goldmine for research on brain diseases<figure><img src="https://images.theconversation.com/files/557356/original/file-20231005-26-rmh9lm.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4000%2C1508&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The experimental methods available today allow us to break the brain down into its elementary components in order to understand its functions and dysfunctions.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Human beings have always been fascinated by the brain. </p>
<p>Although scientific knowledge about this 1.3 kg of fragile substance embedded in our cranium has long been incomplete, dazzling technical breakthroughs made in recent years are now ushering in a Golden Age of molecular neuroscience. </p>
<p>These breakthroughs have been made possible partly thanks to brain banks, which preserve human brains in the best possible conditions for scientific research. Here in Montréal, we have one of the world’s largest such banks, the Douglas-Bell Canada Brain Bank (DBCBB), <a href="https://douglasbrainbank.ca">founded in 1980 at the Douglas Hospital</a>. </p>
<p>The DBCBB, which receives several brains each month, has collected over 3,600 specimens to date. Every year, its team processes dozens of tissue requests from scientists in Québec, Canada and abroad, preparing some 2,000 samples for research. </p>
<p>Over the past 40 years, these efforts have led to a considerable number of discoveries about different neurological and psychiatric diseases. </p>
<p>As a full professor in the department of psychiatry at McGill University, researcher at the Douglas Research Centre and director of the DBCBB since 2007, I work in close collaboration with <a href="https://www.mcgill.ca/psychiatry/gustavo-turecki">Dr. Gustavo Turecki</a>, co-director of the DBCBB and responsible for the component devoted to psychiatric illnesses and suicide.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&rect=14%2C2%2C1535%2C1231&q=45&auto=format&w=1000&fit=clip"><img alt="cerebral hemisphere" src="https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&rect=14%2C2%2C1535%2C1231&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=475&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=475&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=475&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=596&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=596&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552153/original/file-20231004-17-mdh992.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=596&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Douglas-Bell Canada Brain Bank, which receives several brains each month, has collected over 3,600 specimens to date.</span>
<span class="attribution"><span class="source">(Naguib Mechawar)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>A brief history of research on the human brain</h2>
<p>Scientists only began to identify the microscopic elements that make up the human brain in the second half of the 19th century. </p>
<p>That was when brains were preserved for the first time in formalin, a solution that preserves biological tissue so that it can be handled more easily and stored over a longer term.</p>
<p>At the same time, precision instruments and protocols were being developed that made it possible to examine the microscopic characteristics of nervous tissue.</p>
<p>Until the middle of the 20th century, researchers were mainly satisfied with preserving the brains of patients, taken during autopsies, so they could use them to identify possible macroscopic or microscopic changes linked to either neurological or psychiatric symptoms.</p>
<p>This is in fact what the German neurologist Alois Alzheimer did when he analyzed the brain of one of his patients suffering from dementia. In 1906, he described, for the first time, the microscopic lesions which characterize the disease that now bears his name.</p>
<p>Until the end of the 1970s, numerous collections of brain specimens preserved in formalin were built in hospital environments, a bit like the cabinets of curiosities of olden days.</p>
<p>Towards the end of the 20th century, new experimental approaches were developed allowing the high-resolution analysis of cells and molecules within biological tissues.</p>
<p>It then became necessary to collect and preserve human brains, obtained with the consent of the individual or his or her family, in conditions compatible with modern scientific techniques.</p>
<p>Researchers began freezing one of the cerebral hemispheres in order to measure its various molecular components. The other hemisphere was preserved in formalin to be used for macroscopic and microscopic anatomical studies.</p>
<p>This was the context in which the Douglas-Bell Canada Brain Bank was created.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The DBCBB premises" src="https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552154/original/file-20231004-25-z5k7jp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Montréal is home to one of the world’s largest brain banks, the Douglas-Bell Canada Brain Bank, which was founded in 1980 at the Douglas Hospital.</span>
<span class="attribution"><span class="source">(Naguib Mechawar)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>New experimental approaches are yielding results</h2>
<p>Leading researchers from many universities around the world now use DBCBB samples to advance their research. This, of course, includes a number of teams in Québec.</p>
<p>For example, with his team from the Douglas Research Centre, which is affiliated with McGill University, <a href="https://douglas.research.mcgill.ca/judes-poirier/">Judes Poirier</a> discovered that the APOE4 gene is a <a href="https://doi.org/10.1016/0140-6736(93)91705-Q">risk factor for Alzheimer’s disease</a>. More recently, the team of <a href="https://crhmr.ciusss-estmtl.gouv.qc.ca/en/researcher/gilbert-bernier">Gilbert Bernier</a>, professor in the department of neuroscience at Université de Montréal, discovered that the lesions characteristic of this disease are associated with <a href="https://doi.org/10.1038/s41598-018-37444-3">abnormal expression of the BMI1 gene</a>.</p>
<p>With regard to psychiatric illnesses, and more specifically depression, major progress has been made recently by the <a href="https://douglas.research.mcgill.ca/mcgill-group-suicide-studies-mgss/">McGill Group for Suicide Studies</a>. </p>
<p>Using cutting-edge methods to isolate and analyze human brain cells, Turecki’s team has succeeded in precisely identifying the cell types whose function is affected in men <a href="https://doi.org/10.1038/s41593-020-0621-y">who have suffered from major depression</a>, and then discovering that the cell types involved in this illness differ <a href="https://doi.org/10.1038/s41467-023-38530-5">between men and women</a>. </p>
<p>These experimental approaches generate huge data sets that can be examined in subsequent studies. This is the case, for example, of work carried out in my laboratory, which identified signs of persistent changes in neuroplasticity within the prefrontal cortex of people with a history of <a href="https://doi.org/10.1038/s41380-021-01372-y">child abuse</a>. In fact, the studies mentioned above enabled us to discover at least one of the cell types involved in this phenomenon. </p>
<p>In short, the experimental methods we have today allow us to break the brain down into its elementary components in order to understand its functions and dysfunctions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Cerebral hemispheres preserved in formalin" src="https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552155/original/file-20231004-27-62uc6y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Leading researchers from many universities around the world benefit from Douglas-Bell Canada Brain Bank samples to advance their research.</span>
<span class="attribution"><span class="source">(Naguib Mechawar)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>Identify, prevent, screen and treat</h2>
<p>Thanks to the hard work and dedication of the entire DBCBB team, as well as the unfailing support of all its partners, patrons (often anonymous) and funding bodies — particularly the FRQS research fund and Québec’s suicide research network, the <a href="https://reseausuicide.qc.ca">Réseau québécois sur le suicide, les troubles de l'humeur et les troubles associés</a> — this invaluable resource has not only managed to survive, but to grow and become one of the largest brain banks in the world. </p>
<p>There is every reason to believe that, in the years to come, the DBCBB will play an important role in the increasingly precise identification of the biological causes of brain diseases, and, as a result, will contribute to the identification of new targets for better approaches to prevention, screening and treatment.</p><img src="https://counter.theconversation.com/content/216980/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Naguib Mechawar has received funding from CIHR, NSERC, HBHL (CFREF) and FQRS (NEURON ERA-NET and RQSHA).</span></em></p>Montréal is home to one of the world’s largest brain banks, the Douglas-Bell Canada Brain Bank, where discoveries about different neurological and psychiatric diseases are made.Naguib Mechawar, Neurobiologiste, Institut Douglas; Professeur titulaire, Département de psychiatrie, McGill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2173382023-11-24T11:28:26Z2023-11-24T11:28:26ZWeird and wonderful things lost then found inside the human body<figure><img src="https://images.theconversation.com/files/561415/original/file-20231123-29-r1n543.jpg?ixlib=rb-1.1.0&rect=19%2C0%2C4341%2C2909&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/nervous-patient-about-be-examined-by-94281856">Lisa F. Young/Shutterstock</a></span></figcaption></figure><p>Doctors in Missouri recently made a startling discovery. A 63-year-old patient who went for a routine colon screening was found to have an <a href="https://journals.lww.com/ajg/fulltext/2023/10000/to_be_a_fly_on_the_wall__a_mysterious_finding_on.7.aspx">intact fly</a> in his colon. The doctors had no idea how the fly survived the perilous journey through the patient’s digestive enzymes and stomach acid.</p>
<p>As a professor of anatomy, I come across many such stories of strange things found inside people – foreign bodies, we call them. Here is a roundup of some of them.</p>
<p>A lady in Taiwan recently made the news because a <a href="https://www.nejm.org/doi/full/10.1056/NEJMicm2307942">spider and its exoskeleton</a> were found inside her ear. Spiders inside the body are fairly rare, and those with <a href="https://my.clevelandclinic.org/health/diseases/21852-arachnophobia-fear-of-spiders">arachnophobia</a> will be pleased to hear that, despite what some say, we don’t eat <a href="https://www.bbc.co.uk/news/uk-england-beds-bucks-herts-66319172">eight spiders a year in our sleep</a>. </p>
<p>However, one unfortunate <a href="https://www.bbc.co.uk/news/uk-england-beds-bucks-herts-66319172">British postman</a> had an unpleasant result of swallowing a spider, which bit him causing his throat to swell and impair breathing.</p>
<p>While the person giving a home to a spider had little choice in the matter, other people often find themselves ingesting or inhaling things they didn’t mean to. The vast majority of these people are children, particularly when <a href="https://pubmed.ncbi.nlm.nih.gov/29205569/">learning to wean</a>. </p>
<p>Sadly, the location of these objects in the respiratory tract is one of the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8883880/">most common causes of death</a> in children under three years of age.</p>
<p>Children tend to place things in their mouths, noses and ears. Things in the mouth and nose typically get inhaled and lodge in the respiratory tract, usually causing choking, which expels the object. </p>
<p>The things children are likely to inhale range from the familiar (toys, beads, magnets) to the unexpected (<a href="https://pubmed.ncbi.nlm.nih.gov/36164319/">leeches</a> and <a href="https://www.sciencedirect.com/science/article/pii/S2210261223003425">needles</a>). And inhaled items vary by region. In western countries, it is <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012369215352934?via%3Dihub">peanuts</a> that are inhaled the most, with <a href="https://pubmed.ncbi.nlm.nih.gov/6708272/">hotdogs causing most deaths</a>. </p>
<p>In <a href="https://shc.amegroups.org/article/view/6248/html">south-east Asia and China</a> it is bones and seeds, with most cases occurring around <a href="https://pubmed.ncbi.nlm.nih.gov/19197090/">lunar new year</a>. And in Middle Eastern, <a href="https://www.sciencedirect.com/science/article/pii/S2405844023083366">African</a> and Mediterranean countries it is typically <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503708/">nuts</a> or <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6559979/">seeds</a>. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/14649474/">Several</a><a href="https://pubmed.ncbi.nlm.nih.gov/8678434/">studies</a> have also shown that males are far more likely to inhale things than females.</p>
<p>Accidentally inhaling things is also an increasing risk as people get older and lose <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2804956/">muscle tone</a>. Things sometimes end up going “down the wrong way” – most notably food items, but things such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4608337/">dentures</a> have been lost too.</p>
<p>In some instances, things a child accidentally inhales can go unnoticed for decades. A postman from Preston, England, inhaled a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5747653/">Playmobil road</a> cone as a child, but it was only discovered when the 47-year-old had his lungs scanned when he presented with a persistent cough.</p>
<p>While not 40 years in the finding, a man <a href="https://www.theguardian.com/world/2010/aug/12/pea-sprouts-man-lung">inhaled a pea</a>, which was in place long enough for it to begin to sprout in his respiratory tract.</p>
<figure class="align-center ">
<img alt="Image of a dead fly inside a man's colon." src="https://images.theconversation.com/files/561411/original/file-20231123-15-2w1hoz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561411/original/file-20231123-15-2w1hoz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=230&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561411/original/file-20231123-15-2w1hoz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=230&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561411/original/file-20231123-15-2w1hoz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=230&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561411/original/file-20231123-15-2w1hoz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=290&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561411/original/file-20231123-15-2w1hoz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=290&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561411/original/file-20231123-15-2w1hoz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=290&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A dead but fully intact fly inside a man’s transverse colon.</span>
<span class="attribution"><a class="source" href="https://journals.lww.com/ajg/_layouts/15/oaks.journals/ImageView.aspx?k=ajg:2023:10000:00007&i=inline-graphic1&year=2023&issue=10000&article=00007">Official journal of the American College of Gastroenterology</a></span>
</figcaption>
</figure>
<h2>Swallowed items</h2>
<p>Although inhalation is a common reason for things to end up in the body that shouldn’t be there, swallowing them is another common route. </p>
<p>Children are again the most likely group to end up in A&E due to swallowing foreign objects, such as <a href="https://pubmed.ncbi.nlm.nih.gov/16140701/">coins</a> or <a href="https://publications.aap.org/pediatrics/article/143/5/e20181988/77066/">small toys</a>. Most of these items will pass harmlessly through the digestive tract. </p>
<p>About 20% end up needing to be retrieved using an endoscope (a tube inserted into the mouth or anus), and 1% need surgery. </p>
<p>Magnets pose a greater risk when <a href="https://www.sciencedirect.com/science/article/pii/S1875957220300966">more than one</a> has been consumed because they can attract each other through the loops of the bowel wall, causing tears in the bowel.</p>
<p>Ingestion of metallic objects that become lodged, without symptoms, can pose a future risk if they contain <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8373193/">ferrous metals</a>, making them magnetic. If the person has an MRI scan, they can become dislodged or heat up, <a href="https://pubmed.ncbi.nlm.nih.gov/37876260/">causing damage</a>.</p>
<h2>…and at the other end</h2>
<p>While things going in the mouth represent one entry point to the body, some people lose objects at the other end. This can be the vagina or the rectum. </p>
<p>Vaginal foreign bodies represent those that are medically necessary and those that are there for other reasons. Typical vaginal foreign bodies include <a href="https://www.ajog.org/article/S0002-9378(22)02547-9/fulltext">pessaries</a> or <a href="https://pubmed.ncbi.nlm.nih.gov/30324812/">damaged intrauterine contraceptive</a> devices that the patient may forget or not realise are broken.</p>
<p>They pose long-term risks to the patient from <a href="https://www.jamda.com/article/S1525-8610(15)00022-5/fulltext">infection</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/29458888/">fistulas</a> (an abnormal opening between one hollow organ and another or between a hollow organ and the surface of the skin), and <a href="https://www.birpublications.org/doi/10.1259/bjrcr.20150474">stone formation</a> (calculi).</p>
<p>At this end of the body, there are also things found in the anus and rectum. Between <a href="https://www.sciencedirect.com/science/article/abs/pii/S0039610909001571?via%3Dihub">66%</a> and <a href="https://publishing.rcseng.ac.uk/doi/10.1308/rcsann.2020.7129">85%</a> of those attending A&E with this complaint are men. </p>
<figure class="align-center ">
<img alt="X-ray showing a foreign body in a patient's rectum." src="https://images.theconversation.com/files/561404/original/file-20231123-19-w6xkqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561404/original/file-20231123-19-w6xkqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=350&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561404/original/file-20231123-19-w6xkqn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=350&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561404/original/file-20231123-19-w6xkqn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=350&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561404/original/file-20231123-19-w6xkqn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=439&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561404/original/file-20231123-19-w6xkqn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=439&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561404/original/file-20231123-19-w6xkqn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=439&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Up to 85% of people who attend A&E with a foreign body in their anus or rectum are men.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rectal-foreign-bodies-object-rectum-2314265587">therad/Shutterstock</a></span>
</figcaption>
</figure>
<p>One of the biggest issues with foreign objects in the anus and rectum is they can become lodged, blocking the natural movement of intestinal contents. Over time, this can cause significant stretching of the tract and runs the risk of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8728799/">perforating</a> or <a href="https://wjes.biomedcentral.com/articles/10.1186/1749-7922-8-25">tearing</a> the bowels. </p>
<p>There are many reasons people put foreign objects up their anus, ranging from the more common <a href="https://pubmed.ncbi.nlm.nih.gov/29804075/">erotic</a> reasons to the less common <a href="https://www.sciencedirect.com/science/article/pii/S2405469023000195">constipation relief</a>.</p>
<p>While the reasons are diverse, they are surpassed by the variety of objects found at this end, including: <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5081549/">apples</a>, <a href="https://wjes.biomedcentral.com/articles/10.1186/1749-7922-8-11">aubergine, brush, pens</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4641864/">carrots</a>, <a href="https://karger.com/dmj/article/6/1/54/835236/Retained-Pesticide-Bottle-in-the-Rectum">pesticide containers</a>, <a href="https://casereports.bmj.com/content/14/5/e241538">deodorant can</a> (which represents a fire hazard during surgical removal), <a href="https://academic.oup.com/bjs/article/110/1/123/6649749">drinking glass</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2702971/">fizzy drinks bottles</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/832561/">baseball</a> and probably most eye-watering is a whole <a href="https://academic.oup.com/bjs/article/110/1/123/6649749">coconut</a>.</p>
<p>The issue with rectal foreign bodies is that the sphincters that keep your faeces inside, will do the same to objects that are pushed beyond them, many of which stretch the muscle wall of the rectum to the point where it cannot generate enough force to push the object back outside, meaning surgeons usually have to <a href="https://www.degruyter.com/document/doi/10.1515/iss-2017-0021/html?lang=en">open the patient up to retrieve the item</a>.</p>
<p>So, whether by accident or on purpose, things going into the body present a risk of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9795131/">death</a> from <a href="https://bestpractice.bmj.com/topics/en-gb/653">choking</a> through to bleeding to death. If an object is inhaled, ingested or inserted by accident or on purpose it should be reason enough to seek medical assistance. Flies, though, we can’t do much about.</p><img src="https://counter.theconversation.com/content/217338/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An intact fly was recently found inside a man’s colon. It joins a long list of odd things found inside the human body.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2165892023-11-01T17:04:03Z2023-11-01T17:04:03ZThe best techniques for being a cricket fast bowler, according to science<p>Twenty years ago, Shoaib Akhtar became the <a href="https://www.espncricinfo.com/story/shoaib-akhtar-at-100-mph-126897">first person recorded to bowl at 100mph (161km per hour)</a> during the 2003 One-Day International Men’s World Cup match for Pakistan against England. There was an expectation afterwards that this feat would become a regular occurrence.</p>
<p>As humans have continued to run faster, throw further and jump higher, it was believed that this milestone would be a stepping stone consigned to history similar to Roger Bannister <a href="https://www.guinnessworldrecords.com/records/hall-of-fame/first-sub-four-minute-mile">breaking the four-minute mile</a>. It was thought it might also act as a catalyst for serious worldwide improvement in fast bowling.</p>
<p>However, despite continuing improvement in the athletic ability of fast bowlers, the magical three-figure barrier has only been surpassed since by Brett Lee and Shaun Tait – and not for over ten years.</p>
<p>Has cricket fast bowling’s top speed stalled? During the current <a href="https://www.cricketworldcup.com/">2023 One-Day International Men’s World Cup</a> being hosted in India, only a handful of bowlers have produced speeds over 90mph (145km per hour), with the fastest being around 95mph (153 km per hour).</p>
<p>The performance of cricket fast bowlers almost entirely depends on two factors. The first is the amount of momentum developed in the run-up and maintained before the front foot contacting the floor. The second is the technique employed to generate and transfer momentum within the body <a href="https://en.wikipedia.org/wiki/Bowling_action#/media/File:Bowling_action.png">during the bowling phase</a> between the front foot contacting the floor and the release of the ball from the bowler’s hand. </p>
<p><a href="https://journals.humankinetics.com/view/journals/jab/29/1/article-p78.xml">Previous research</a> has highlighted that the fastest elite male bowlers generate more momentum in their run-up, adopting a movement strategy that aims to maintain and transfer this momentum into the throw instead of generating additional momentum from their muscles.</p>
<h2>Testing the limits</h2>
<p>To investigate the limits of fast bowling performance, a <a href="https://linkinghub.elsevier.com/retrieve/pii/S0021929023003354">world-leading predictive musculoskeletal computer simulation model</a> of ten elite male fast bowlers (essentially a virtual clone of each bowler) was developed. It then optimised their technique to maximise the release speed of the ball. </p>
<p>Significantly, none of these bowlers were predicted by the computer model to break the 100mph barrier.</p>
<p>To understand why the top speed has stalled, it is important to consider how all the factors influencing human movement patterns affect the technique of fast bowlers. </p>
<p><a href="https://link.springer.com/article/10.2165/00007256-200333040-00001">The behaviour of all our movement patterns</a> is shaped by three types of constraint. The first is organismic: these are constraints on the individual, such as their size, strength and range of motion. The second factor shaping movement patterns is the environment the individual interacts with, including the atmosphere, temperature, equipment and surfaces. The third shaping factor is the task, which involves constraints such as the goal of the activity, the rules and the intensity. </p>
<p>Our previous experiences of the movement – what we have seen, what we have been told and our previous performance of the movement – also affect individual technique in fast bowling.</p>
<p>The innate physiology of the fast bowler, an organismic constraint, provides the only potential area for development in fast bowling. The other constraints, such as environment and task, which often lead to scientific and technological development associated with improvements in other sports, are extremely limited in fast bowling. This is due to the lack of equipment and the simplicity of the activity.</p>
<p>The physiological aspect often considered to be associated with improvements in fast bowling performance is an increase in muscular strength, power and endurance. However, there’s a unique cricket bowling “task” constraint which requires bowlers to maintain a straight arm during the bowling phase. This significantly reduces the time available to complete the throwing movement. </p>
<h2>Explosive activation</h2>
<p>Elite males <a href="https://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1522700">complete the bowling phase in approximately 100 milliseconds</a>. This is similar to the time required to explosively activate a single muscle. This limits the ability of bowlers to develop additional momentum using their muscles in the bowling phase and neutralises the effect of strength increases on ball speed. </p>
<p>This explains why maximising momentum generated during the run-up is preferred over generating muscular momentum during the bowling phase. It also explains why fast bowling top speeds have not increased despite recent advances in fast bowlers’ athletic abilities.</p>
<p>Interestingly, <a href="https://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1522700">research on women fast bowlers</a> has highlighted that bowlers who generate less momentum during the run-up and therefore have more time available to generate additional muscular momentum, adopt a movement pattern <a href="https://journals.assaf.org.za/index.php/sajsm/article/view/15080">more akin to throwing</a>. In this approach, the momentum generated in the run-up is added to via the use of large rotational torso muscles within the bowling phase. </p>
<p>Improvements to the performance of the large rotational torso muscles in men and women could possibly improve the generation of muscular momentum. But this approach is considered a sub-optimal technique by the research that’s been carried out on fast bowling.</p>
<p>A potential mechanism to increase the time available to develop more momentum from muscles would be to increase the range of motion that joints move through during the bowling phase. </p>
<h2>Joint ‘hypermobility’</h2>
<p><a href="https://www.tandfonline.com/doi/full/10.1080/02640414.2023.2200520">Recent research has highlighted</a> that, on average, elite fast bowlers with an increased range of motion in the hip and shoulder had greater ball release speeds. It was also suggested that the bowlers’ techniques were probably influenced by their range of motion during their early learning years. </p>
<p>In addition, elbow hyperextension – where the joint travels beyond a straight position – <a href="https://www.tandfonline.com/doi/abs/10.1080/02640414.2015.1137340">has been shown to increase the speed of ball release</a> by up to 5% during the bowling phase. A common misconception, however, is that taller bowlers will bowl faster due to the benefit associated with increased limb length.</p>
<p>Unfortunately, as limbs get longer, they get more difficult to rotate. As muscular strength does not scale equally with limb length this becomes a disadvantage. Thus, an optimal height for fast bowlers probably exists, though we don’t know what it is.</p>
<p>Organismic factors linked with increased ball speed such as body shape, size and hypermobility are largely genetic. Since human evolution is extremely slow, advances in ball release speed are likely to follow at a similar pace. </p>
<p>The 100mph barrier, therefore, should be viewed more as a mountain that requires a once-every-generation bowler to scale rather than a dam in a river. The potential of this peak to grow is limited by the constraints of the task and by our innate physiology.</p><img src="https://counter.theconversation.com/content/216589/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Felton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Why the speed of fast bowling in cricket seems to have stalled.Paul Felton, Senior Lecturer in Biomechanics in the School of Science and Technology, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2105292023-10-25T12:31:23Z2023-10-25T12:31:23ZFrom morgue to medical school: Cadavers of the poor, Black and vulnerable can be dissected without consent<figure><img src="https://images.theconversation.com/files/555053/original/file-20231020-25-57ohdr.jpg?ixlib=rb-1.1.0&rect=8%2C5%2C1964%2C1302&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Medical students look at cadaver parts being used for demonstration.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/meley-bekele-can-hardly-stand-to-look-at-the-cadaver-parts-news-photo/165288427?adppopup=true">Rick Madonik/Toronto Star via Getty Images</a></span></figcaption></figure><p>Every year, first-year medical students approach their human cadavers with a mixture of awe and trepidation. They will come to know their assigned cadaver intimately. During the course of their studies, they will carefully pull back layers of skin, muscle and tissue as they learn the fundamentals of human anatomy.</p>
<p>When the long process of dissection is complete, the cadavers are cremated, <a href="https://theconversation.com/medical-students-honor-body-donors-through-words-deeds-and-ceremonies-208168">with the remains</a> returned to family, interred in a dedicated plot, scattered in a memorial garden or sometimes buried at sea.</p>
<p>Historically, anatomy laboratories relied on unclaimed bodies or executed prisoners, and even resorted to grave-robbing <a href="https://theconversation.com/from-grave-robbing-to-giving-your-own-body-to-science-a-short-history-of-where-medical-schools-get-cadavers-199947">to meet the growing demand for cadavers</a>. Today, while we’d like to believe every cadaver on the slab has been donated knowingly – and indeed, <a href="https://www.nationalgeographic.com/science/article/body-donation-cadavers-anatomy-medical-education">thousands of Americans will leave their bodies to science every year</a> – the reality is more complicated. </p>
<p>In the United States, when a deceased person’s assets are insufficient to cover the cost of burial or cremation, and next of kin are unable or unwilling to shoulder the financial burden, it falls to the state or county in which the person died to arrange for the disposal of their remains. </p>
<p>In most parts of the country, government officials are permitted to donate these unclaimed bodies to institutions of higher education, with no legal requirement for prior consent from the deceased or their next of kin. In 2019, <a href="https://doi.org/10.1002/ase.1853">12.4% of surveyed U.S. medical schools</a> indicated possible use of unclaimed bodies at their institutions. </p>
<p>As <a href="https://www.uta.edu/academics/faculty/profile?username=shupee">a professional medical ethicist</a>, I was surprised when I learned in 2021 about the continuing use of unclaimed bodies in medical teaching, and I set out to discover the extent to which the practice occurred in Texas, where I live and work. Those efforts culminated in <a href="https://doi.org/10.1001/jama.2023.15132">a peer-reviewed, comprehensive study</a> on cadaver procurement trends within a single state, and what our research team found was alarming.</p>
<p>Between 2017 and 2021, the number of unclaimed bodies accepted by Texas medical schools increased nearly sevenfold. It rose from 64 to 446 – going from 2.27% of all donations to 14.12% – over five years.</p>
<h2>Money plays a role</h2>
<p>Budgetary pressures have likely played some role in driving these trends. In the United States, <a href="https://choicemutual.com/blog/cremation-cost/">the average cost of a no-frills cremation is currently around US$2,000</a>. Some states or counties offer burial for unclaimed bodies if there is reason to believe the deceased wouldn’t want cremation, such as for religious reasons, but it is a more expensive option, with the money coming from the county or state budget. </p>
<p>Not only do medical schools cremate the bodies they accept without charge, but many also offer discount-rate cremation for bodies that are offered but do not meet their requirements for human cadavers. </p>
<p>In densely populated areas with a greater number of unclaimed bodies, these savings can add up. Tarrant County, Texas – home to the city of Fort Worth – has <a href="https://fortworthreport.org/2022/04/03/cadavers-help-students-prepare-for-professions-in-medicine-but-some-are-donated-without-consent/">saved hundreds of thousands of dollars each year</a> through its agreement with a local medical school. </p>
<h2>Ethical controversies</h2>
<p>Concerningly, medical students are sometimes <a href="https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ase.1853">kept in the dark</a> about the use of unclaimed bodies at their own institutions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&rect=6%2C6%2C2116%2C1851&q=45&auto=format&w=1000&fit=clip"><img alt="Two medical students, intently looking down, with one covering her mouth with one hand." src="https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&rect=6%2C6%2C2116%2C1851&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=529&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=529&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=529&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=665&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=665&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555051/original/file-20231020-23-zytvm6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=665&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">First-year medical students at their first anatomy class.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-university-of-minnesota-class-of-2004-following-the-news-photo/1154189048?adppopup=true">Judy Griesedieck/Star Tribune via Getty Images</a></span>
</figcaption>
</figure>
<p>Mary Peeler, who graduated from the Johns Hopkins University School of Medicine, learned from a teaching assistant that her cadaver had been an unclaimed body only after she had already begun the process of dissection. </p>
<p>“I still grapple,” <a href="https://pubmed.ncbi.nlm.nih.gov/33207091/">she wrote</a> in the New England Journal of Medicine, “with the guilt of having dissected a man who may have wanted to rest in peace.”</p>
<p>What little we know about the demographics of unclaimed bodies suggests that they are <a href="https://doi.org/10.1371/journal.pone.0238348">more likely to be male, more likely to be African American and more likely to have been poor or unemployed prior to death</a> than bodies that are claimed by next of kin. Some who have <a href="https://doi.org/10.1002/ca.21223">spoken out</a> have emphasized that it is disproportionately society’s most vulnerable members who may be dissected without consent.</p>
<p>The International Federation of Associations of Anatomists has released <a href="https://ifaa.net/recommendations/">professional guidelines</a> calling for anatomists to stop using unclaimed bodies, and a handful of medical schools have independently decided to no longer accept them. Oregon Health & Science University, for example, <a href="https://www.oregonlive.com/portland/2009/01/ohsu_stops_taking_bodies_of_in.html">stopped taking unclaimed bodies</a> in 2009 after the sister of a man whose remains were mistakenly donated to the university came forward.</p>
<h2>Bans on the use of unclaimed bodies</h2>
<p>If the use of unclaimed bodies is on the rise in Texas, is the same thing happening elsewhere? For now, we simply do not know. The donation of unclaimed bodies remains legal in the majority of U.S. states, although there are some outliers.</p>
<p>In 2016, <a href="https://www.nytimes.com/2016/08/20/nyregion/law-bans-the-use-of-unclaimed-dead-as-cadavers-without-consent.html">New York banned</a> the use of unclaimed bodies without written consent from the deceased or their next of kin, a move that faced strong opposition from the state’s consortium of 16 medical schools. A few other states, <a href="https://legiscan.com/HI/bill/SB2818/2012">including Hawaii</a> in 2012 and <a href="https://legislature.vermont.gov/bill/status/2014/H.178">Vermont in 2014</a>, have passed similar pieces of legislation.</p>
<p>In 2021, I chose to donate my own body to science. Signing the paperwork attesting that I was of sound mind and fully informed about my decision required a half-hour of my time and the presence of two witnesses. It is unsettling that many Americans may have made that exact “donation” without ever having had to put a pen to paper. Instead, all they needed to do was die poor and alone.</p><img src="https://counter.theconversation.com/content/210529/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eli Shupe does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Most states permit government officials to donate unclaimed bodies to medical schools, with no legal requirement for prior approval from the deceased or their next of kin.Eli Shupe, Assistant Professor of Philosophy and Co-Director of Medical Humanities and Bioethics, University of Texas at ArlingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124202023-09-04T17:37:53Z2023-09-04T17:37:53ZDogs don’t see life through rose-coloured glasses, nor in black and white<p>For a few months now, I’ve been treating six-year-old Samuel, who has the beginnings of myopia. He’s very quick for his age and often asks me questions about tests I give him, and about what I see inside his eyes. </p>
<p>But the last question surprised me. </p>
<p>Samuel knows that some people, like his father, don’t see colours well. But what about his little poodle, Scotch, he asked?</p>
<p>I’m not a veterinarian and don’t want to intrude on their domain of expertise. However, as an optometrist, I can offer some insights that might help answer Samuel’s question. </p>
<h2>Cones and rods</h2>
<p>Ambient light is composed of <a href="https://www.britannica.com/science/photon">particles (photons)</a>, which line up in rays. Light rays travel and strike objects. Some rays are absorbed, while others are reflected, depending on the characteristics of their surfaces and the composition of their materials. The wavelengths of the reflected rays determine the colour of the object as it is perceived by the eye. </p>
<p>Like everything about human vision, colour perception is complex. The retina, the sensitive part that lines the back of the eye, has two types of photon receptors: cones and rods. The cones, in the centre of the retina (fovea), perceive bright light and are <a href="https://askabiologist.asu.edu/rods-and-cones">responsible for colour perception</a>.</p>
<p>There are three types of cones. Each type contains a specific photo-pigment called opsin, which defines its nature. The opsin is produced under the influence of specific genes. The shortest opsin (“Cone S” for <em>short</em>) reacts mainly to blue light (420 nm). The longer one (“Cone L”) is more sensitive to orange-red light (560 nm) and the one in between (“Cone M” for <em>middle</em>) <a href="https://opentextbc.ca/biology/chapter/17-5-vision/">is activated in the presence of green (530 nm)</a>.</p>
<p>However, each cone reacts to each of the rays entering the eye. For example, a red ball will produce a weak response from the S cone (3/10), a slightly stronger response from the M cone (5/10) and a <a href="https://opentextbc.ca/biology/chapter/17-5-vision/">strong response from the L cone</a> (8/10). </p>
<p>The brain combines the signals emitted by each of these cones to form the colour it perceives. So, in the previous example, the perceived colour would be coded 3-5-8, corresponding to what we know as red. A pink colour might have the code 4-6-6, and blue, 8-6-3. Each combination of the 3-cone signals is unique, which allows us to appreciate different hues in all their variations. </p>
<p>That is, as long as the genetic code is intact. </p>
<p>The genes associated with colour vision can be mutated or defective, in which case the person will be partially or completely impaired. The best known of these anomalies is colour blindness (red-green deficiency or daltonism).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="perception of a plant according to a colour-blind person" src="https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=331&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=331&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=331&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=415&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=415&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544341/original/file-20230823-249-j6j8jf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=415&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Colour blindness is associated with difficulty in perceiving red and green.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>And what about animals?</h2>
<p>Colour vision, in humans as in animals, <a href="https://www.discoverwildlife.com/animal-facts/animal-vision-how-do-animals-see/">has developed throughout evolution</a> and results from the needs of each species according to their environment, the prey they hunt and the threats they need to avoid.</p>
<p>For example, birds have a fourth opsin that allows them to see ultraviolet (UV) light. Humans cannot perceive this light because our crystalline (internal) lens <a href="https://www.nwf.org/Magazines/National-Wildlife/2012/AugSept/Animals/Bird-Vision">filters UV rays</a>. UV rays influence birds’ behavioural decisions, including foraging and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0065345408601059#:%7E:text=Publisher%20%20Summary,light%2C%20depending%20on%20the%20species.">their choice of a mate</a>.</p>
<p>So the colour vision of birds is more complex, with the result that the pigeon, which can perceive a myriad of colours, wins the <a href="https://nuscimagazine.com/the-world-through-the-eyes-of-a-pigeon/#:%7E:text=Though%20this%20range%20of%20vision,is%20one%20of%20these%20animal">award for best color vision among all species</a>.</p>
<p>Insects also perceive UV light. This function is essential for them to spot pollen, although their colour vision is very poor. Their eyes are made up of multiple lenses (ommatidia) that perceive <a href="https://www.mpg.de/14337047/how-flies-see-the-world">more movement than colour</a>. That’s much more practical while in fast flight.</p>
<p>Most forest-dwelling mammals have only two opsins. That’s because they lost the one associated with orange-red over the course of evolution. This explains why, unlike humans, these animals don’t perceive the orange bibs of hunters. </p>
<p>Snakes, on the other hand, are more sensitive to red and infrared light, thanks to their infrared receptors. This is an advantage when it comes to spotting prey, as <a href="https://phys.org/news/2006-08-snakes-vision-enables-accurate-prey.html">they can distinguish their heat even at night</a>. </p>
<p>Unsurprisingly, it’s the monkey that’s closest to the human, with its three opsins. It is said to be trichromatic. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="close-up of a black dog's eyes" src="https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544344/original/file-20230823-19-pd8rjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dogs only perceive yellow-green and violet-blue. Colours are perceived as paler, like pastels.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Back to Scotch</h2>
<p>The vision of dogs — such as our friend Scotch — is <a href="https://ophtalmoveterinaire.com/maladies_oculaires/vision-comment-voit-mon-chien/#:%7E:text=For%20r%C3%A9sumer%2C%20the%20vision%20of,for%20his%20life%20of%20dog.">quite different</a>. </p>
<p>Unlike humans, dogs’ eyes are located on the side of the skull. As a result, dogs have a wider field of vision (250 to 280 degrees), but less simultaneous vision. </p>
<p>So Scotch’s vision of movement is well developed throughout his visual field. But his central vision is actually six times weaker than ours. This is equivalent to the vision of a very myopic person not wearing glasses. Why? Because the dog’s retina contains no fovea, and therefore fewer cones. </p>
<p>But while dogs eyes have fewer cones, they have more rods. And as an added bonus, they have an extra layer of the retina, called the tapetum lucidum — or carpet. When combined, these ingredients mean dogs see better in dim light and at night. This layer receives light and reflects it back onto the retina for a second exposure. This explains why your dog’s eyes seem to glow at night.</p>
<p>When it comes to colours, dogs are dichromats. They perceive only yellow-green and violet-blue. Colours are perceived paler, like pastels. And some colours don’t contrast: that’s why a red ball on green grass will appear to them as pale yellow on a grey background, with little contrast.</p>
<p>So it’s possible, depending on the colour of the ball, that Scotch will not see it, and as a result, will gaze up at Samuel with a lost look. As for the infrared, he perceives heat through his nose, not through his eyes.</p>
<p>Cats are also dichromats. Their vision is therefore similar to that of dogs, but their colour palette is different — more oriented towards violet and green. Having no perception of red-green, they are essentially colour-blind. They are also very short-sighted. Their clear vision is limited to a few meters in front of them.</p>
<p>Throughout cats’ evolution, other senses came to compensate for this. Among other things, although they only perceive certain contrasts, they are <a href="https://www.wired.com/2013/10/cats-eye-view/">formidable at perceiving movement</a>. Mice move quickly! </p>
<p>Every species adapts to its environment, and humans are no exception. Who knows what our colour vision will be like 500 years from now, after we’ve been exposed to more and more electronic devices and artificial colours? </p>
<p>But that’s a question for Samuel to answer when he’s older.</p><img src="https://counter.theconversation.com/content/212420/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Langis Michaud ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Your faithful companion sees the world differently than you do, but it’s a mistake to assume dogs only see black, white and shades of grey.Langis Michaud, Professeur Titulaire. École d'optométrie. Expertise en santé oculaire et usage des lentilles cornéennes spécialisées, Université de MontréalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2097042023-08-24T10:52:28Z2023-08-24T10:52:28ZWhat your hands say about your health<p>Your hands reveal a lot about the state of your health. This is something that has been recognised since at least the time of Hippocrates – the father of modern medicine.</p>
<p>The ancient Greek physician <a href="https://jamanetwork.com/journals/jama/fullarticle/1150736">first described “clubbing”</a> in a patient with empyema (where pus fills the space between the lungs and the membrane around it) in the fifth century BC. Clubbing is where the nail looks like an upside-down spoon, and it is still recognised as a sign of disease. Although nowadays, clubbing is linked to more than just empyema. It is also <a href="https://my.clevelandclinic.org/health/symptoms/24474-nail-clubbing">linked to</a> cystic fibrosis, cirrhosis of the liver and thyroid conditions.</p>
<p>Another nail change that can signal disease is Lindsay’s nails. This is where one or more nails are half white and half reddish brown. Around
<a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ccr3.4426#ccr34426-bib-0007">50%</a> of people with <a href="https://www.nejm.org/doi/full/10.1056/nejmicm1406572">chronic kidney disease</a> have nails like this. But it can also be a sign of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8183706/">cirrhosis of the liver</a> and <a href="https://journal.chestnet.org/article/S0012-3692(15)41065-7/fulltext">Behcet’s disease</a>, a rare condition that causes inflammation of the blood vessels.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/13153107/">Terry’s nails</a>, where <a href="https://www.ccjm.org/content/ccjom/81/10/603.full.pdf">one or more fingernails</a> have a ground-glass appearance, can also be a sign of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025669/">cirrhosis of the liver</a>, but they are also associated with type 2 diabetes, kidney failure and HIV. </p>
<figure class="align-right ">
<img alt="Terry's nails" src="https://images.theconversation.com/files/539806/original/file-20230727-23-j6jvf4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/539806/original/file-20230727-23-j6jvf4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539806/original/file-20230727-23-j6jvf4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539806/original/file-20230727-23-j6jvf4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539806/original/file-20230727-23-j6jvf4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539806/original/file-20230727-23-j6jvf4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539806/original/file-20230727-23-j6jvf4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Typical ground glass appearance of Terry’s nails.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=22101599">Hojasmuertas/Wikimedia commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>And sounding a bit more medical and a bit less like a high street nail bar is <a href="https://www.ncbi.nlm.nih.gov/books/NBK559136/">Muehrcke’s nails</a>, which is where one or more horizontal lines run across the fingernails. This nail pattern indicates a decrease in the most abundant protein in the blood: <a href="https://www.ncbi.nlm.nih.gov/books/NBK459198/">albumin</a>. These nail markings can be an indicator of <a href="https://www.amjmed.com/article/S0002-9343(10)00297-4/fulltext">kidney disease</a>.</p>
<p>But sometimes changes in nail colour and pattern are not sinister and are merely signs of ageing. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038811/">Neapolitan nails</a>, so called because of their three distinct colour zones, are often seen in people over the age of 70 and are nothing to worry about.</p>
<h2>Palms</h2>
<p>Nails aren’t the only part of the hand that can reveal ill health, though. The palms can tell a story too.</p>
<p>If you find your palms are becoming sweaty in the absence of nervousness, hot temperatures or exercise, it could be down to faulty nerve signals causing the sweat glands to become active. This can be benign, in which case it is called primary hyperhidrosis. But unexplained sweaty palms – and face, neck and armpits – can be a sign of thyroid problems. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/books/NBK279480/">Hyperthyroidism</a> is where the thyroid gland in the neck produces too much <a href="https://www.ncbi.nlm.nih.gov/books/NBK500006/">thyroxine</a>. Excess of this hormone causes bodily processes to speed up and can be the cause of sweaty palms. Thankfully, this condition is easily treated with the right drugs. </p>
<p>A more concerning palm change is the appearance of small areas of red or purple discolouration on the palms of the hands and fingers. This can be a sign of bacterial <a href="https://www.nhs.uk/conditions/endocarditis/">endocarditis</a> (inflammation of the inside lining of the heart), which has a high <a href="https://bmccardiovascdisord.biomedcentral.com/articles/10.1186/s12872-021-01853-6">mortality rate</a>. </p>
<p>These discolourations come in two forms: <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603816/">Osler’s nodes</a> and <a href="https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.112.127787">Janeway lesions</a>. Osler’s nodes are typically painful <a href="https://link.springer.com/article/10.1007/s11739-014-1063-x">red 1mm-10mm</a> coloured nodules on the fingers appearing for hours to days, whereas Janeway lesions are <a href="https://heart.bmj.com/content/91/4/516">irregular shaped with varying sizes</a> and typically seen on the palms and are not painful, lasting few days up to a few weeks.</p>
<p>Both these palm patterns are very serious and urgent medical attention should be sought. </p>
<h2>Pins and needles</h2>
<p>If you experience pins and needles in your hand that you can’t shake off, it might be a sign that you have <a href="https://www.nhs.uk/conditions/carpal-tunnel-syndrome/">carpal tunnel syndrome</a>. This is where a major nerve (the median nerve) in the wrist is being compressed, causing numbness, tingling or pain. </p>
<p>It usually gets better without treatment, but a wrist splint can help to relieve pressure on the nerve. People who are overweight or pregnant are at greater risk of carpal tunnel syndrome.</p>
<p>Pins and needles in the hand can also be a sign of diabetes. Raised blood sugar in diabetes causes <a href="https://www.webmd.com/diabetes/peripheral-neuropathy-risk-factors-symptoms">nerve damage</a> that manifests as <a href="https://www.nature.com/articles/s41572-019-0092-1">tingling or numbness</a> in the extremities, such as the hands. This condition is called “diabetic neuropathy”. </p>
<p>Everyone experiences pins and needles at some point, but if you get it a lot or it lasts a long time, you should see your doctor.</p>
<h2>Finger length</h2>
<p>The length of your fingers can give you some indication of your risk of developing certain diseases in later life. </p>
<p>The length of the index versus ring finger varies in men and women. In women, they are fairly equal in length, but in men, the ring finger is typically longer than the index finger. This is believed to be due to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5296424/">exposure to hormones in the womb</a>.</p>
<figure class="align-center ">
<img alt="Finger length comparison" src="https://images.theconversation.com/files/539916/original/file-20230728-21-ku5ia8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539916/original/file-20230728-21-ku5ia8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539916/original/file-20230728-21-ku5ia8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539916/original/file-20230728-21-ku5ia8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539916/original/file-20230728-21-ku5ia8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=431&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539916/original/file-20230728-21-ku5ia8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=431&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539916/original/file-20230728-21-ku5ia8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=431&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Your finger length can reveal how much testosterone you were exposed to in the womb.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/different-length-finger-index-ring-2132603433">logika600/Shutterstock</a></span>
</figcaption>
</figure>
<p>This longer ring than index finger relationship is associated with better performance in a <a href="https://pubmed.ncbi.nlm.nih.gov/16403410/">number of sports</a> in men and women, but also a risk of <a href="https://pubmed.ncbi.nlm.nih.gov/18163515/">developing knee and hip osteoarthritis</a> in women.</p>
<p>There is nothing you can do to change your finger length, but you can help stave off osteoarthritis by keeping a healthy weight, staying active and controlling your blood sugar levels. In fact, if you stick to that advice, you can stave off most illness.</p><img src="https://counter.theconversation.com/content/209704/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Since the time of Hippocrates, doctors have looked at patients hands for signs of ill health.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2100842023-08-18T14:43:47Z2023-08-18T14:43:47ZWhy we think that some extinct giant flying reptiles cared for their young<figure><img src="https://images.theconversation.com/files/543063/original/file-20230816-28-82uhml.jpg?ixlib=rb-1.1.0&rect=9%2C0%2C6082%2C2931&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pteranodon was a large-bodied pterosaur.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pteranodon-flying-genus-pterosaur-lived-during-2133739385">YuRi Photolife / Shutterstock</a></span></figcaption></figure><p>Our understanding of animal behaviour depends on observation. Researchers can study how animals are born, grow and develop. We can gather evidence of how they interact with each other and their environment.</p>
<p>But how do we do this for extinct animals? <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2023.1102">In a recent scientific paper</a>,
palaeontologist <a href="https://www.ucc.ie/en/mariamcnamara/whoweare/zixiao/">Zixiao Yang</a> and colleagues compared the growth of small and giant pterosaurs. </p>
<p>These were flying reptiles that were alive between about 228 million years ago and 66 million years ago – sharing the Earth with dinosaurs. Yang and colleagues wanted to understand what, if anything, was different about how the giant animals got so big.</p>
<figure class="align-center ">
<img alt="Pterosaur" src="https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=368&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=368&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=368&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=462&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=462&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543263/original/file-20230817-23-q0f85v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=462&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Model pterosaur, Dimorphodon macronyx (reconstruction). Photographed at the National Museum of Scotland.</span>
<span class="attribution"><a class="source" href="https://www.jasongilchrist.co.uk/Blog_386348.html">Jason Gilchrist</a></span>
</figcaption>
</figure>
<p>They looked at the limb bones, which are critical to locomotion: the forelimbs to flight, the hindlimbs to movement on the ground. With the smaller-bodied pterosaurs (the smallest in the study had a wingspan of 0.19–0.74 metres), they discovered that the limb bones that lay closest to the body – the “proximal” ones – grew more slowly relative to their total body size as the animals aged after hatching.</p>
<p>For large-bodied pterosaur species, such as <a href="https://www.britannica.com/animal/Pteranodon"><em>Pteranodon</em></a>, with a wingspan range of 3.91-6.37 metres, the limb bones that lay closest to the body grew faster than other elements of their skeleton after hatching.</p>
<figure class="align-center ">
<img alt="Limb bone growth allometry in pterosaurs of different sizes. The wings of small-bodied pterosaurs show limb bones that grew slowly with respect to the rest of the body, indicating that they were potentially good fliers soon after hatching. Large-bodied pterosaur species, however, were born with relatively small arms. Even though their wing bones grew quickly after hatching relative to the rest of the body, the young of these species likely could not fly as efficiently and therefore parental care may have been required." src="https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=348&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=348&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=348&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=438&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=438&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543289/original/file-20230817-30641-1dr1ti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=438&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Infographic showing different growth patterns in large and small pterosaurs.</span>
<span class="attribution"><span class="source">Yang Z, Jiang B, Benton MJ, Xu X, McNamara ME, Hone DWE.</span></span>
</figcaption>
</figure>
<p>In bird and mammal species alive today, this pattern is associated with particular developmental strategies. Present-day species showing a developmental pattern most similar to the smaller pterosaurs tend to <a href="https://web.stanford.edu/group/stanfordbirds/text/uessays/uPrecocial_and_Altricial.html">move around independently</a> from an early age.</p>
<p>While not necessarily lacking in parental care, such species tend to be less dependent on or demanding of their parents. By contrast, living species showing the developmental pattern seen in the larger <em>Pteranodon</em> tend to have young that are not capable of independent movement. In these animals, intensive parental care – including feeding the young – is the norm.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/dinosaur-egg-bonanza-gives-vital-clues-about-prehistoric-parenting-121401">Dinosaur egg bonanza gives vital clues about prehistoric parenting</a>
</strong>
</em>
</p>
<hr>
<h2>Wing development</h2>
<p>Using data from fossils, Yang and colleagues used computers to model the body measurements of different pterosaur species as they grew.</p>
<p><em>Pteranodon</em>‘s wing aspect ratio (the wing length relative to wing area) increased as the species grew, allowing it to develop a long, narrow wing, associated with soaring in modern birds. The smaller pterosaurs, however, showed a consistent or decreasing wing aspect ratio during growth, allowing more manoeuvrability.</p>
<p>These developmental differences between larger and smaller species of pterosaur indicate that <em>Pteranodon</em>’s relatively greater proximal limb growth shortly after hatching, along with – perhaps – enhanced parental care, may have helped it reach a large adult size. Pterosaurs as a group encompassed the largest flying animals of all time. <em><a href="https://link.springer.com/article/10.1007/s00114-002-0307-1">Hatzegopteryx thambema</a></em> may have been the biggest, with a wingspan of up to 12 metres. But all pterosaurs started small.</p>
<p>Pterosaur hatchlings’ size was limited by ultimately the size of their eggs, which was constrained by the size of the pelvic opening of female pterosaurs, and by the <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(14)00525-9">soft eggshell produced by pterosaurs</a>. Compared to hard-shelled bird eggs, soft eggs are weaker and cannot support larger sizes. To grow big, pterosaurs had to do most of their growing after they hatched.</p>
<h2>Parental care</h2>
<p>A key difference between the small and large species may have been parental care. This may have released large pterosaurs from growth and size constraints. An extended maturation period where parents protected their young and fed them may have allowed a bending of developmental physics, resulting in a larger body size, a lighter skeleton and more robust joints. In contrast, small pterosaur species by the nature of their slower proximal limb growth may have been locked into maturity at smaller sizes.</p>
<p>It’s also possible that baby pterosaurs from larger species with parental care were not capable of flight, whereas smaller species were <a href="https://www.nature.com/articles/s41598-021-92499-z">flight-ready upon hatching</a>.</p>
<p>To grow to such a large body size, the giant pterosaurs also needed two things from their environment: space and updrafts. Big pterosaurs would principally have been soarers, meaning that they used updrafts to stay aloft and economised on energy by minimising flapping. Giant pterosaurs also needed a food supply to support their large size and fuel their metabolic requirements.</p>
<p>While competitors for food were likely in short supply for large adult pterosaurs, youngsters – being smaller – would be more likely to overlap in terms of food sources and habitats with smaller pterosaur species. Young giant pterosaurs probably <a href="https://tetzoo.com/blog/2021/7/21/baby-pterosaurs-were-excellent-fliers-and-occupied-different-niches-from-their-parents">did not compete for food with adult pterosaurs of the same species</a>.</p>
<p>Predation on adult giant pterosaurs by other animals would have been limited. What dinosaurs (or other creatures) would have been big and hard enough to take on such an imposing sharp-beaked monster?</p>
<figure class="align-center ">
<img alt="Pteranodon longiceps being preyed on by a Cretoxyrhina shark." src="https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543066/original/file-20230816-22-6737f1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Large pterosaurs like Pteranodon probably had only a handful of predators, such as this large shark.</span>
<span class="attribution"><a class="source" href="https://www.markwitton.co.uk/">Mark Witton</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Future fossils</h2>
<p>Incredible as it seems, we can infer the presence of parental care – and lack thereof – in long-dead species of flying reptile. The odds of a pterosaur being preserved in the act of unambiguous parental care seem incredibly slim. So evidence from fossils and understanding patterns from contemporary species are critical to our understanding.</p>
<p>At some point, someone will hopefully find juvenile giant pterosaurs, and their hatchlings, eggs and embryos. Otherwise, questions will remain regarding the development of baby pterosaurs.</p>
<p>These questions include: what was the nature of the parental care? Did parents keep eggs and young warm by sitting over them? Did they defend juveniles against predators, providing food for pterosaur babies? Did males and females share parental care equally? Did they care for young that were not their own?</p>
<p>To more fully re-imagine the early lives and parental behaviour of giant pterosaurs, we need more fossils. Let’s find them.</p><img src="https://counter.theconversation.com/content/210084/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Gilchrist does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Reptiles don’t generally care for their offspring, but some pterosaurs may have bucked the trend.Jason Gilchrist, Lecturer in the School of Applied Sciences, Edinburgh Napier UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1711922023-06-30T12:37:43Z2023-06-30T12:37:43ZIs it legal to sell human remains?<figure><img src="https://images.theconversation.com/files/534894/original/file-20230629-29-fif855.jpg?ixlib=rb-1.1.0&rect=9%2C15%2C2108%2C1393&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The handling and disposition of human bodies raises all sorts of ethical and legal questions.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/coffin-on-stage-royalty-free-image/85637547?phrase=funeral&adppopup=true">Jupiterimages/The Image Bank via Getty Images</a></span></figcaption></figure><p>Four individuals were <a href="https://media.wbur.org/wp/2023/06/morgue-indictment.pdf">charged with federal crimes</a> in June 2023 related to the “unlawful transport” across state lines of human remains taken from the Harvard Medical School morgue. This indictment was part of a larger effort by the Department of Justice to <a href="https://www.justice.gov/usao-mdpa/pr/six-charged-trafficking-stolen-human-remains">shut down a national network</a> of people trafficking in human remains. </p>
<p>Cedric Lodge, who had been the morgue manager <a href="http://hms.harvard.edu/news-events/anatomical-gift-program-resources/frequently-asked-questions">until his firing in May</a>, was accused of removing human remains that had been donated to the medical school. According to <a href="https://media.wbur.org/wp/2023/06/morgue-indictment.pdf">the indictment</a>, he and his wife, Denise Lodge, shipped those remains to Katrina MacLean, the owner of a store called Kat’s Creepy Creations, and Joshua Taylor, an individual living in Pennsylvania. Taylor transferred nearly US$40,000 to the Lodges via PayPal, with memos that included “head number 7” and “braiiiiiins.”</p>
<p>As a scholar whose research is centered on the <a href="https://law.wfu.edu/faculty/profile/marshtd/">laws regarding the status, treatment and disposition of human remains</a>, I am often asked about the legality and ethics of <a href="https://www.huffpost.com/entry/laws-permitting-human-remains_b_1769082">selling bodies</a>, especially when stories like the <a href="https://www.boston.com/news/crime/2023/06/16/is-it-legal-to-sell-human-remains-harvard-morgue-scandal-raises-questions/">Harvard morgue case</a> or <a href="https://abcnews.go.com/US/tiktok-user-sells-human-bones-ignites-ethical-debate/story?id=80541972">a TikTok user selling human bones</a> begin to circulate.</p>
<p>My answers often surprise people.</p>
<h2>State by state</h2>
<p>It is not illegal to sell human remains under federal law. That’s why the defendants in the Harvard Medical School case were <a href="https://www.justice.gov/usao-mdpa/pr/six-charged-trafficking-stolen-human-remains">charged with interstate transport of stolen goods</a>, rather than “trafficking human remains.” </p>
<p>There is actually very little federal law regarding the dead. The most significant is the Federal Trade Commission’s <a href="https://www.ftc.gov/news-events/topics/truth-advertising/funeral-rule">Funeral Rule</a>, which requires funeral homes to provide certain disclosures to consumers.</p>
<p>Instead, the vast majority of law respecting the dead is state law, which varies significantly.</p>
<p>By my count, the sale of human remains is broadly and expressly illegal in only eight states: <a href="http://www.leg.state.fl.us/Statutes/index.cfm?App_mode=Display_Statute&Search_String=&URL=0800-0899/0872/Sections/0872.01.html#:%7E:text=View%20Entire%20Chapter,775.082%20or%20s.">Florida</a>, <a href="https://codes.findlaw.com/ga/title-31-health/ga-code-sect-31-21-41/">Georgia</a>, <a href="https://malegislature.gov/Laws/GeneralLaws/PartIV/TitleI/Chapter272/Section72">Massachusetts</a>, <a href="https://www.revisor.mo.gov/main/OneSection.aspx?section=194.410&bid=10000&hl=#:%7E:text=194.410.,commits%20a%20class%20E%20felony.">Missouri</a>, <a href="https://www.revisor.mo.gov/main/OneSection.aspx?section=194.410&bid=10000&hl=#:%7E:text=194.410.,commits%20a%20class%20E%20felony.">New Hampshire</a>, <a href="https://www.scstatehouse.gov/code/t44c043.php">South Carolina</a>, <a href="https://casetext.com/statute/texas-codes/penal-code/title-9-offenses-against-public-order-and-decency/chapter-42-disorderly-conduct-and-related-offenses/section-4208-abuse-of-corpse#:%7E:text=Section%2042.08%20%2D%20Abuse%20of%20Corpse%20(a)%20A%20person%20commits,illegally%20disinterred%3B%20(3)%20sells">Texas</a> and <a href="https://law.lis.virginia.gov/vacode/title32.1/chapter8/section32.1-303/">Virginia</a>. </p>
<p>Perhaps one reason the Harvard morgue case is being handled by the Department of Justice is that although selling human remains is illegal in Massachusetts and New Hampshire, it does not violate state law in Pennsylvania, where some of the activity took place.</p>
<p>In more than two dozen other states, <a href="https://www.lawyersandjudges.com/products/the-law-of-human-remains">it is illegal to sell human remains</a> only under certain circumstances. A number of these states make it expressly illegal to sell human remains or organs that were donated for anatomical study, transplantation or medical therapy. </p>
<p>Most commonly, it is illegal to sell human remains that have been unlawfully removed from a place of burial. For example, in <a href="https://www.ncleg.gov/EnactedLegislation/Statutes/PDF/ByArticle/Chapter_70/Article_3.pdf">North Carolina</a>, it is a crime to “knowingly exhibit or sell any human skeletal remains from unmarked burials.” However, this specific phrasing means that the North Carolina law could not be applied to a situation like the Harvard case, where the body was obtained from a morgue. Nor could it be applied to the sale of body parts other than skeletal remains.</p>
<h2>Up for sale</h2>
<p>In fact, it is surprisingly easy to purchase human remains in the United States, even in states where such sales are expressly illegal. There are brick-and-mortar stores, like <a href="https://www.cbsnews.com/boston/news/katrina-maclean-peabody-creepy-dolls-store-charged-harvard-morgue-body-part-theft/">Kat’s Creepy Creations</a> in Massachusetts, which sell skeletal remains. </p>
<p>But increasingly, retail traffic in human remains <a href="https://doi.org/10.1111/1556-4029.13147">takes place online</a>. The sales of human remains have been banned on Etsy and eBay <a href="https://money.cnn.com/2012/08/10/technology/etsy-bans-drugs/index.html">since 2012</a> <a href="https://www.buzzfeednews.com/article/danvergano/skull-sales">and 2016</a>, respectively, but social networks like Facebook are <a href="https://www.livescience.com/human-bone-trade-facebook.html">rife with groups</a> where body parts are sold and traded. One of the defendants in the Harvard Medical School case <a href="https://www.newsweek.com/woman-posted-human-skull-instagram-before-harvard-morgue-indictment-1807078">advertised at least one skull on Instagram</a>.</p>
<p>It is difficult to determine how human remains end up in the retail stream because most body parts for sale have been de-identified. In other words, the seller does not name the deceased person whose remains are being sold and usually does not reveal how the remains were obtained – and there is no law requiring them to do so.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man in a green uniform and cap walks around a tombstone with a small fence around it in a wooded area." src="https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534901/original/file-20230629-26-9mgo4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A historian inspects a Civil War-era grave dug up by grave robbers on National Park Service property in Maryland.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/wheeler8-date-5-31-06-photographer-katherine-frey-the-news-photo/103800735?adppopup=true">Katherine Frey/The The Washington Post via Getty Images</a></span>
</figcaption>
</figure>
<p>There are a few explicitly illegal methods of obtaining human remains in the U.S. Grave robbery, for example, <a href="https://www.lawyersandjudges.com/products/the-law-of-human-remains?_pos=2&_sid=b1c0b1545&_ss=r&variant=6027975619">is specifically outlawed</a> in nearly every state. Digging up corpses was a <a href="https://www.smithsonianmag.com/history/in-need-cadavers-19th-century-medical-students-raided-baltimores-graves-180970629/">significant problem</a> in the 1800s, when medical schools first began <a href="https://theconversation.com/medical-students-honor-body-donors-through-words-deeds-and-ceremonies-208168">to teach students through anatomical dissection</a>.</p>
<p>When a person dies in the U.S., there are limited legal options for the disposition of their body, which effectively prevents an individual from arranging to sell their own remains. </p>
<p>In every state, remains may be buried, entombed, cremated, donated to science or removed from the state or order to be lawfully disposed of elsewhere. More than half of states have legalized a process called <a href="https://www.cremationassociation.org/page/alkalinehydrolysis">alkaline hydrolysis</a>, also known as <a href="https://www.cremationassociation.org/blogpost/776820/313847/What-do-you-know-about-Alkaline-Hydrolysis">aquamation or water cremation</a>, which dissolves the body in a base solution. In seven states, remains may be disposed of via <a href="https://connectingdirectors.com/65987-nevada-legalizes-nor">natural organic reduction</a>, also called <a href="https://www.popsci.com/environment/composting-body-burial/">human composting</a>.</p>
<h2>Final gift</h2>
<p>If an individual or their family donates remains to science, typically a nonprofit organization or university takes possession of the remains.</p>
<p>The use of those remains varies widely. A medical school like Harvard has an <a href="https://meded.hms.harvard.edu/anatomical-gift-program">anatomical donation program</a> to obtain intact cadavers to be used in gross anatomy labs and other teaching settings. </p>
<p>However, people sometimes donate to a non-transplant tissue bank, often called “body brokers.” Given the high costs of funeral arrangements in the U.S., some families donate a loved one’s remains to body brokers, who dispose of remains without cost to the family. </p>
<p>Bluntly speaking, body brokers carve up human remains and distribute them to be used in medical therapy or research, with little regulation – the subject of a <a href="https://www.reuters.com/investigates/special-report/usa-bodies-brokers/">2017 Reuters investigation</a>. They do charge for processing and transporting human remains, and one such company, Science Care, <a href="https://www.reuters.com/investigates/special-report/usa-bodies-science/">generated $27 million in revenue in 2017</a>.</p>
<p>Body brokers are <a href="https://nfda.org/news/media-center/nfda-news-releases/id/7475/congress-takes-significant-step-to-regulate-body-brokers">more controversial</a> than university anatomical donation programs, but in both cases, remains are used for medical education or research. The ultimate disposition of remains donated to science is typically cremation.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A body lies covered by a white sheet on a metal table in a white and yellow lab-like room." src="https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534896/original/file-20230629-25452-4u7cgg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Human remains donated to science are meant to be disposed of with respect.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/pathology-department-in-a-hospital-royalty-free-image/539882937?phrase=morgue&adppopup=true">Team Static/fStop via Getty Images</a></span>
</figcaption>
</figure>
<h2>Seeking justice</h2>
<p>If bodies donated to science are not <a href="https://nfda.org/news/media-center/nfda-news-releases/id/7475/congress-takes-significant-step-to-regulate-body-brokers">treated with the respect and dignity</a> that the donors were promised by the recipient institution, as in the Harvard Medical School case, there are several possible legal options. </p>
<p>First, there could be federal or state criminal charges in the small number of states that broadly outlaw the sale of human remains. </p>
<p>Second, 30 states outlaw the mistreatment or mutilation of human remains. These criminal laws are generally referred to as “<a href="https://funerallaw.typepad.com/blog/2015/10/does-the-law-limit-what-you-can-do-with-human-remains-yes-understanding-abuse-of-corpse-laws.html">abuse of corpse” statutes</a>.</p>
<p>Finally, the families of the donors may have a private cause of action against the recipient institution or against people who took the remains without permission. There are <a href="https://www.ali.org/projects/show/torts-miscellaneous-provisions/">two possible tort claims</a> that families could bring: interference with the family’s right to respectfully dispose of the remains, known formally as “interference with the right of sepulcher,” and infliction of emotional harm based on mistreatment of human remains.</p>
<p>I have yet to encounter a person who is not horrified by the treatment of the bodies donated to Harvard Medical School and then diverted into curiosity shops and private collections, especially when I explain that such activities are not clearly illegal in every state. </p>
<p>Respectful treatment of human remains, and of the loved ones they leave behind, appears to be a universal value. Yet there is a clear mismatch between these social norms and the law – for now.</p><img src="https://counter.theconversation.com/content/171192/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tanya D. Marsh does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The short answer: It’s complicated – and depends, in part, where you live.Tanya D. Marsh, Professor of Law, Wake Forest UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2081682023-06-28T12:34:48Z2023-06-28T12:34:48ZMedical students honor body donors through words, deeds and ceremonies<figure><img src="https://images.theconversation.com/files/534396/original/file-20230627-27-sd4cd.jpg?ixlib=rb-1.1.0&rect=0%2C4%2C1024%2C677&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Donors' bodies lie covered in an anatomy lab at the Justus Liebig University in Giessen, Germany.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/march-2023-hesse-gie%C3%9Fen-couch-with-covered-body-donations-news-photo/1249666093?adppopup=true">Sebastian Gollnow/picture alliance via Getty Images</a></span></figcaption></figure><p><a href="https://www.justice.gov/usao-mdpa/pr/six-charged-trafficking-stolen-human-remains">Six people were charged</a> on June 14, 2023, with buying and selling human remains stolen from the Harvard Medical School morgue and from an Arkansas mortuary. The macabre story <a href="https://apnews.com/article/stolen-human-body-parts-harvard-medical-school-a33afcd82908dda340f4c1df18e7b43f">made national headlines</a>, particularly the indictment of Cedric Lodge: a morgue manager at Harvard from 1995 until earlier this year.</p>
<p>As <a href="https://chaplaincyinnovation.org/team/amy-lawton-phd">a scholar in the sociology of religion</a>, <a href="http://hdl.handle.net/11134/20002:860685608">my research</a> explores practices related to whole-body donation in medical schools across the United States. While these accusations against Lodge are deeply troubling, they are an aberration: Medical school communities go to incredible lengths to respect and honor the people who donate their bodies to science.</p>
<p>Much of this happens behind closed doors. The serious scientific work of anatomical study is undergirded by practices that promote the donors’ dignity, including memorial ceremonies to honor their gift. I conducted <a href="http://hdl.handle.net/11134/20002:860685608">a census of allopathic medical schools</a> – schools that grant the M.D. degree – and analyzed recordings of 60 donor memorial ceremonies, as well as other materials.</p>
<h2>Foundation of learning</h2>
<p>Despite advances made in technology, including virtual reality and 3D anatomy software, dissecting a real human body is generally considered irreplaceable in Western medical education. Substitutions result in <a href="https://doi.org/10.1002/ase.1859">less effective instruction</a>, leading to lower scores on practical and written examinations. One benefit is that <a href="https://doi.org/10.1002/ase.1758">students who learn from dissection</a> see normal bodies, with diversity, variations and imperfections that would not be evident on models. Faculty <a href="http://hdl.handle.net/11134/20002:860685608">views donor bodies as essential</a> because they are always accurate and up to date, which cannot always be said about books or software. </p>
<p>In the U.S., medical schools <a href="https://www.statnews.com/2016/08/17/body-donations-medical-school/">accept bodies from donors</a> and next of kin. A minority of institutions <a href="https://doi.org/10.1002/ase.1853">accept unclaimed bodies</a>, but their use is controversial.</p>
<p>Bodies’ importance goes beyond their effectiveness as a teaching tool. Anatomy lab marks the students’ <a href="https://doi.org/10.1002/ar.b.20117">initiation into the medical profession</a>. It teaches not only anatomy but the value of the human person, professionalism, ethics and clinical skills such as diagnosis. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A young brunette woman wearing gloves rinses a human heart in a sink in an anatomy lab." src="https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534397/original/file-20230627-35262-9zpqxh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The lessons medical students learn from donor bodies go beyond anatomy.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/liz-harkin-uses-a-running-tap-to-clean-out-a-human-heart-news-photo/145376204?adppopup=true">Bill O'Leary/The Washington Post via Getty Images</a></span>
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<p>From day one, medical students studying gross anatomy are encouraged to think of the donor body as <a href="https://www.nytimes.com/2023/05/31/science/donor-bodies-medical-school-appreciation.html">their “first patient</a>,” someone for whom they will care and from whom they will learn. Medical students are responsible for preserving the body, performing dissections correctly so as not to cause unnecessary mutilation, and speaking of the body and the donor respectfully. </p>
<p>Students work in teams, each of which is usually responsible for dissecting one body. Many also feel a sense of responsibility toward their donors – a duty to learn as much as they can, taking full advantage of the gift they have been given.</p>
<h2>Reflection and respect</h2>
<p>At the end of the semester, students say goodbye to the donors. My research found that more than nine out of 10 allopathic medical schools mark this occasion with a memorial ceremony. <a href="https://thedo.osteopathic.org/2018/03/acom-honors-anatomical-donors-memorial-space-reflection/">Ceremonies also take place</a> at schools for other branches of health care, such as <a href="https://www.liberty.edu/lucom/news/lucom-class-of-2024-hosts-annual-symbolic-memorial-honoring-first-patients/">osteopathy</a> and <a href="https://blogs.chapman.edu/crean/2015/04/08/honoring-those-who-give-life-to-science-donor-memorial-ceremony/">physical therapy</a>. Wherever students learn from body donors, they gather together to express their gratitude for a gift that can never be reciprocated.</p>
<p>Some ceremonies are conducted before an audience that includes the friends and families of all body donors used that year. Some are open to the medical school community, and others are for the students alone. For many, these donors have played a transformative role in their lives. It is common to hear students refer to their donors as a friend or mentor. </p>
<p>At the 2018 University of Iowa ceremony, a student reflected: “I know her hands, her feet, what parts of her may have ached towards the end of life, which organs let her down. I spent countless hours as her pupil. She taught me things about life that no living person ever could. When I was confused and needed time to think, she was patient. My donor entrusted me with the intimate gift of her body to learn about the topics that make my heart race.” </p>
<p>Learning in the anatomy lab and participating in a donor memorial ceremony have something important in common. Both experiences <a href="https://www.britannica.com/topic/sacred">stand apart from everyday life</a>, making them, in a sense, sacred. These ceremonies set aside a special time and space for <a href="https://doi.org/10.1002/ar.10188">reflection and remembrance</a> – time and space that busy medical students do not usually have.</p>
<p>Unlike most memorial services, these students have no personal memories of the deceased. In fact, some are not even told their donor’s first name, which is often concealed to preserve privacy.</p>
<p>Yet they know at least one fact: This person cared about medicine and other people’s health. Students reflect on how generous and principled the donors must have been – as well as their families, who were willing to carry out loved ones’ wishes in their time of grief. Though students did not witness donors’ lives, they can still <a href="http://hdl.handle.net/11134/20002:860685608">celebrate and honor them</a>. </p>
<p>A student at the University of Cincinnati’s 2019 service shared: “I am overwhelmed with respect and gratitude for all our donors. … As we gather here today, let’s remember the legacy that all of these donors and family members have left in all of us, and celebrate the legacy that they continue to forge even after death.” </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Rows of young people in white medical coats stand respectfully outside at a ceremony." src="https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=356&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=356&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=356&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=448&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=448&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534452/original/file-20230627-27-jgyme6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=448&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Medical students at the University of Mississippi Medical Center attend the Ceremony of Thanksgiving in Memory of Anatomical Donors in 2018.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/HonoringTheirGifts/57639ee975e143e6b8acc8d0048f069b/photo?Query=donor%20body%20ceremony&mediaType=photo&sortBy=arrivaldatetime:desc&dateRange=Anytime&totalCount=41&currentItemNo=7">AP Photo/Rogelio V. Solis</a></span>
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</figure>
<p>A donor body’s gift cannot be “paid back,” but medical students can try to pay it forward. Many describe ways they will try to serve others, as the donor did. Some doctors-to-be express a sense that the donors will forever guide their hands.</p>
<p>There is no foolproof way to prevent bad actors in any institution. Yet research into donor memorial ceremonies shows that no one takes the gift of body donation more seriously than the recipients.</p><img src="https://counter.theconversation.com/content/208168/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amy Lawton received funding from the Templeton Religion Trust administered through the Issachar Fund.</span></em></p>The lessons students learn from dissecting donor bodies go beyond anatomy – and they try to pay that gift forward.Amy Lawton, Research Manager, Chaplaincy Innovation Lab, Brandeis UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2005442023-05-26T00:52:27Z2023-05-26T00:52:27ZCurious Kids: how does your brain know how to move your body?<figure><img src="https://images.theconversation.com/files/527875/original/file-20230523-28-11kgez.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5742%2C3819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-girl-climbing-rock-wall-indoor-1253459440">Shutterstock</a></span></figcaption></figure><p><em>How does your brain know how to move your body? – Ivy, age 8, Victoria</em></p>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png" width="100%"></a></p>
<p>Hi Ivy, thanks for asking such an interesting question!</p>
<p>To answer it, we’ll need to look at some different parts of the brain and what they do.</p>
<h2>First, the brain collects information</h2>
<p>The front part of the brain plans and makes decisions. It does this after considering the different types of information it receives from “nerve cells”. </p>
<p>This information is called “sensory” information. It comes from touch, pain, temperature, hearing, seeing, and so on.</p>
<p>This is what happens when, for example, we spot someone giving out chocolate on the street, we turn our heads to look at them and walk towards the chocolate.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-much-does-a-brain-weigh-112000">Curious Kids: how much does a brain weigh?</a>
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</em>
</p>
<hr>
<h2>So how do the messages get from the brain?</h2>
<p>The brain lives in the brain box in our head. The spinal cord lives in the spinal canal, in the back part of our body. </p>
<p>Tiny nerve fibres that come out of the lower part of the brain and the spinal cord connect many muscles. When they tighten, they make things move. </p>
<p>Some nerve fibres connect to muscles that cross the joints. Others attach to the tongue and eyeball and make them move. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/527874/original/file-20230523-27-x1e6b5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527874/original/file-20230523-27-x1e6b5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527874/original/file-20230523-27-x1e6b5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527874/original/file-20230523-27-x1e6b5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527874/original/file-20230523-27-x1e6b5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527874/original/file-20230523-27-x1e6b5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527874/original/file-20230523-27-x1e6b5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The brain stem is the bit at the bottom of the brain.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/anatomy-human-brain-vector-illustration-basic-75070678">Shutterstock</a></span>
</figcaption>
</figure>
<p>Nerve cells send signals among each other, and between all the muscles and glands, including those responsible for making saliva in the mouth and digestive juices in the stomach.</p>
<p>A human brain has <a href="https://www.sciencedirect.com/science/article/pii/B9780128110164000039">more than 100 billion</a> nerve cells and sends messages to make us do things like walk, skip or stand up from a chair.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-is-a-headache-is-it-our-brain-hurting-112951">Curious Kids: what is a headache? Is it our brain hurting?</a>
</strong>
</em>
</p>
<hr>
<h2>Different jobs for different parts of the brain</h2>
<p>The brain has many regions that coordinate how we move. </p>
<p>One part helps us work out how much force is necessary in making the movement. It also tells the brain to start the movement. </p>
<p>Another part plays a role in the timing of movements.</p>
<figure class="align-center ">
<img alt="Children looking at things in the garden with a magnifying glass" src="https://images.theconversation.com/files/527876/original/file-20230523-25-g01082.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/527876/original/file-20230523-25-g01082.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527876/original/file-20230523-25-g01082.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527876/original/file-20230523-25-g01082.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527876/original/file-20230523-25-g01082.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527876/original/file-20230523-25-g01082.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527876/original/file-20230523-25-g01082.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Different parts of the brain have different jobs in helping us move.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/two-children-boy-girl-warm-hats-2027604446">Shutterstock</a></span>
</figcaption>
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<p>Different types of nerves also have different roles. Some help us move voluntarily – when we choose to. These nerves connect to the muscles responsible for moving our joints in different body parts, like our arms and legs. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-when-i-stop-spinning-why-do-i-feel-dizzy-and-the-world-looks-like-its-tilting-154559">Curious Kids: when I stop spinning, why do I feel dizzy and the world looks like it’s tilting?</a>
</strong>
</em>
</p>
<hr>
<p>Another group of nerves work automatically. They sense what is happening inside our body without us consciously knowing. These nerves control the muscles in our heart, blood vessels, stomach, intestines, kidneys and other organs, helping them work properly.</p>
<h2>What’s the answer in a nutshell?</h2>
<p>So Ivy, to sum up, the brain receives information from our senses and uses this to control our body movements. </p>
<p>Different parts of the brain send messages to different parts of the body to get these movements right. </p>
<p>Our brain can also store movements into memories that will be recalled for future use. That’s why you can remember how to ride a bike, even if you haven’t ridden one for months. </p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p><img src="https://counter.theconversation.com/content/200544/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arjun Burlakoti does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>To answer this question, we’ll need to look at some different parts of the brain and what they do.Arjun Burlakoti, Senior Lecturer in Anatomy and Neuroanatomy, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2020112023-04-05T12:24:51Z2023-04-05T12:24:51ZRacist and sexist depictions of human evolution still permeate science, education and popular culture today<figure><img src="https://images.theconversation.com/files/518818/original/file-20230331-1042-s84ty.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C1367&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Human evolution is typically depicted with a progressive whitening of the skin, despite a lack of evidence to support it.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Stone_age_by_Vasnetsov_01.jpg">Viktor Mikhailovich Vasnetsov/Wikimedia Commons</a></span></figcaption></figure><p>Systemic racism and sexism have <a href="https://doi.org/10.1007/978-3-319-70401-2">permeated civilization</a> since the rise of agriculture, when people started living in one place for a long time. Early Western scientists, such as Aristotle in ancient Greece, were indoctrinated with the <a href="http://www.beacon.org/Superior-P1495.aspx">ethnocentric</a> and <a href="https://www.akpress.org/a-brief-history-of-misogyny.html">misogynistic</a> narratives that permeated their society. More than 2,000 years after Aristotle’s writings, <a href="http://www.beacon.org/Inferior-P1278.aspx">English naturalist Charles Darwin</a> also extrapolated the sexist and racist narratives he heard and read in his youth to the natural world. </p>
<p>Darwin presented his biased views as scientific facts, such as in his 1871 book “<a href="https://www.worldcat.org/title/39301709">The Descent of Man</a>,” where he described his belief that men are evolutionarily superior to women, Europeans superior to non-Europeans and hierarchical civilizations superior to small egalitarian societies. In that book, which <a href="https://www.smithsonianmag.com/science-nature/how-darwins-descent-man-holds-150-years-after-publication-180977091/">continues to be studied</a> in schools and natural history museums, he considered “the hideous ornaments and the equally hideous music admired by most savages” to be “not so highly developed as in certain animals, for instance, in birds,” and compared the appearance of Africans to the New World monkey <em>Pithecia satanas</em>.</p>
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<figcaption><span class="caption">Science isn’t immune to sexism and racism.</span></figcaption>
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<p>“The Descent of Man” was published during a moment of societal turmoil in continental Europe. In France, the working class <a href="https://www.britannica.com/event/Commune-of-Paris-1871">Paris Commune</a> took to the streets asking for radical social change, including the overturning of societal hierarchies. Darwin’s claims that the subjugation of the poor, non-Europeans and women was the natural result of evolutionary progress were music to the ears of the elites and those in power within academia. Science historian <a href="https://scholar.google.com/citations?user=OCG87poAAAAJ&hl=en">Janet Browne</a> wrote that Darwin’s <a href="https://press.princeton.edu/books/paperback/9780691114392/charles-darwin">meteoric rise within Victorian society</a> did not occur despite his racist and sexist writings but in great part because of them. </p>
<p>It is not coincidence that Darwin had a state funeral in Westminster Abbey, an honor emblematic of English power, and was <a href="https://www.worldcat.org/title/darwin/oclc/644948405">publicly commemorated</a> as a symbol of “English success in conquering nature and civilizing the globe during Victoria’s long reign.” </p>
<p>Despite the significant societal changes that have occurred in the last 150 years, sexist and racist narratives are still common in <a href="https://doi.org/10.1002/evan.21978">science, medicine and education</a>. As a <a href="https://scholar.google.com/citations?user=sOat2IwAAAAJ&hl=en">teacher and researcher</a> at Howard University, I am interested in combining my main fields of study, <a href="https://www.ruidiogolab.org/">biology and anthropology</a>, to discuss broader societal issues. In research I recently published with my colleague <a href="https://profiles.howard.edu/fatimah-jackson">Fatimah Jackson</a> and three medical students at Howard University, we show how racist and sexist narratives are not a thing of the past: They are still present in scientific papers, textbooks, museums and educational materials.</p>
<h2>From museums to scientific papers</h2>
<p>One example of how biased narratives are still present in science today is the numerous depictions of human evolution as a linear trend from darker and more “primitive” human beings to more “evolved” ones with a lighter skin tone. Natural history <a href="https://www.voanews.com/a/john-gurche-shaping-humanity/1836128.html">museums</a>, <a href="https://medium.com/paperkin/where-is-evolution-taking-the-human-race-6ddaf7eaddba">websites</a> and <a href="https://theculturetrip.com/africa/south-africa/articles/what-south-africas-caves-can-tell-you-about-humankind/">UNESCO heritage sites</a> have all shown this trend.</p>
<p>The fact that such depictions are not scientifically accurate does not discourage their continued circulation. <a href="https://www.yahoo.com/video/15-countries-largest-white-population-195712421.html">Roughly 11%</a> of people living today are “white,” or European descendants. Images showing a linear progression to whiteness do not accurately represent either human evolution or what living humans look like today, as a whole. Furthermore, there is no scientific evidence supporting a progressive skin whitening. <a href="https://doi.org/10.1002/ajpa.24564">Lighter skin pigmentation</a> chiefly evolved within just a few groups that migrated to non-African regions with high or low latitudes, such as the northern regions of America, Europe and Asia.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/2aFfDooTIVQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Illustrations of human evolution tend to depict progressive skin whitening.</span></figcaption>
</figure>
<p>Sexist narratives also still permeate academia. For example, in a 2021 paper on a famous early human fossil <a href="https://doi.org/10.4436/jass.99001">found in the Sierra de Atapuerca</a> archaeological site in Spain, researchers examined the canine teeth of the remains and found that it was actually that of a girl between 9 and 11 years old. It was previously believed that the fossil was a boy due to a popular 2002 book by one of the authors of that paper, paleoanthropologist <a href="https://scholar.google.com/citations?user=5nDp-kIAAAAJ">José María Bermúdez de Castro</a>. What is particularly telling is that the study authors recognized that there was no scientific reason for the fossil remains to have been designated as a male in the first place. The decision, they wrote, “<a href="https://newsrnd.com/news/2021-03-16-%0A---the-boy-from-the-gran-dolina-was-actually-a-girl%0A--.Skx4GEFC7u.html">arose randomly</a>.”</p>
<p>But these choices are not truly “random.” Depictions of human evolution <a href="https://www.cornellpress.cornell.edu/book/9780801435492/ancestral-images/">frequently only show men</a>. In the few cases where women are depicted, they tend to be shown as passive mothers, not as active inventors, cave painters or food gatherers, despite available anthropological data showing that <a href="http://www.beacon.org/Inferior-P1278.aspx">pre-historical women were all those things</a>.</p>
<p>Another example of sexist narratives in science is how researchers continue to discuss the “puzzling” <a href="https://doi.org/10.1002/jez.b.22690">evolution of the female orgasm</a>. Darwin <a href="https://doi.org/10.1007/978-3-319-70401-2">constructed narratives</a> about how women were evolutionarily “coy” and sexually passive, even though he acknowledged that females actively select their sexual partners in most mammalian species. As a Victorian, it was difficult for him to accept that women could play an active part in choosing a partner, so he argued that such roles only applied to women in early human evolution. According to Darwin, men later began to sexually select women.</p>
<p>Sexist narratives about women being more “coy” and “less sexual,” including the idea of the female orgasm as an evolutionary puzzle, <a href="https://www.iflscience.com/female-orgasms-are-not-puzzling-enigmas--43486">are contradicted</a> by a wide range of evidence. For instance, women are the ones who actually more frequently experience <a href="https://doi.org/10.1080/00224499.2020.1743224">multiple orgasms</a> as well as more <a href="https://doi.org/10.1080/00224490209552129">complex, elaborate and intense orgasms</a> on average, compared to men. Women are not biologically less sexual, but <a href="https://theconversation.com/data-should-smash-the-biological-myth-of-promiscuous-males-and-sexually-coy-females-59665">sexist stereotypes</a> were accepted as scientific fact.</p>
<h2>The vicious cycle of systemic racism and sexism</h2>
<p>Educational materials, including textbooks and anatomical atlases used by science and medical students, play a crucial role in perpetuating biased narratives. For example, the 2017 edition of “<a href="https://evolve.elsevier.com/cs/product/9780323547086?role=student">Netter Atlas of Human Anatomy</a>,” commonly used by medical students and clinical professionals, includes about 180 figures that show skin color. Of those, the vast majority show male individuals with white skin, and only two show individuals with “darker” skin. This perpetuates the depiction of white men as the anatomical prototype of the human species and fails to display the full anatomical diversity of people.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/mMVzPCOut1w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Textbooks and educational materials can perpetuate the biases of their creators in science and society.</span></figcaption>
</figure>
<p>Authors of teaching materials for children also replicate the biases in scientific publications, museums and textbooks. For example, the cover of a 2016 coloring book entitled “<a href="https://books.google.com/books/about/The_Evolution_of_Living_Things_Coloring.html?id=mOUkMQAACAAJ">The Evolution of Living Things”</a>“ shows human evolution as a linear trend from darker "primitive” creatures to a “civilized” Western man. Indoctrination comes full circle when the children using such books become scientists, journalists, museum curators, politicians, authors or illustrators.</p>
<p>One of the key characteristics of systemic racism and sexism is that it is unconsciously perpetuated by people who often don’t realize that the narratives and choices they make are biased. Academics can address long-standing racist, sexist and Western-centric biases by being both more alert and proactive in detecting and correcting these influences in their work. Allowing inaccurate narratives to continue to circulate in science, medicine, education and the media perpetuates not only these narratives in future generations, but also the discrimination, oppression and atrocities that have been <a href="https://www.smithsonianmag.com/science-nature/disturbing-resilience-scientific-racism-180972243/">justified by them in the past</a>.</p><img src="https://counter.theconversation.com/content/202011/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rui Diogo does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From Aristotle to Darwin, inaccurate and biased narratives in science not only reproduce these biases in future generations but also perpetuate the discrimination they are used to justify.Rui Diogo, Associate Professor of Anatomy, Howard UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1965572023-03-27T19:00:33Z2023-03-27T19:00:33ZWhat causes hiccups and how can you get rid of them?<figure><img src="https://images.theconversation.com/files/513100/original/file-20230302-24-dgnskj.jpg?ixlib=rb-1.1.0&rect=81%2C114%2C5381%2C3522&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/funny-woman-politely-covering-her-mouth-1900937419">Shutterstock</a></span></figcaption></figure><p>We all get hiccups from time to time, and sometimes they just won’t seem to go away. </p>
<p>Hiccups are <a href="https://pubmed.ncbi.nlm.nih.gov/8947969/">involuntary contractions</a> of the diaphragm – the muscle separating your chest from your abdomen, which plays a key role in breathing – followed by a sudden closure of the vocal cords. </p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5677923/">medical term</a> for hiccups is singultus. This derives from the Latin word <em>singult</em> which means “to catch ones breath while sobbing”. </p>
<p>For most of us, hiccups are annoying and don’t last that long. But for some people, they can be persistent, lasting more than two days. </p>
<p>The good news is, there are simple ways to alleviate regular hiccups – and treatments for when they persist. </p>
<h2>What causes hiccups?</h2>
<p>Hiccups are caused by a <a href="https://pubmed.ncbi.nlm.nih.gov/1592073/">reflex arc</a>: a neuromotor pathway that translates a sensation into a physical response. The sensations in this arc come from the brain, ear, nose and throat, diaphragm and organs in the chest and abdomen. </p>
<p>The sensation signals travel to a part of the brain which, along with the top of the spinal cord, is known as the “hiccup centre”. </p>
<p>From the hiccup centre, the signals travel back out to the diaphragm and the muscles that lay between your ribs (intercostal muscles), causing them to twitch. </p>
<p>The twitching of these muscles draws air into the lungs and this sudden inhalation makes the opening between the vocal cords, or glottis, close tightly shut. This rapid closure makes the “hic” sound. </p>
<figure class="align-center ">
<img alt="Sonographer persons pregnancy ultrasound" src="https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513094/original/file-20230302-21-52gq4u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Even fetuses get the hiccups.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/professional-doctor-screening-pregnant-woman-by-594048134">Shutterstock</a></span>
</figcaption>
</figure>
<p>Anything that affects the arc can lead to hiccups. The <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">most common</a> is stretching the stomach from eating a large meal or drinking soft drinks. This means sensation signals from the stomach can trigger off the reflex arc. </p>
<p>Consuming hot chilli pepper, alcohol, smoking, and over-excitement can also <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">trigger</a> the reflex arc, leading to hiccups. </p>
<p>Hiccups have even been <a href="https://pubmed.ncbi.nlm.nih.gov/7383483/">observed</a> in healthy fetuses during prenatal ultrasound checks. In fact, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1891574/pdf/v041p00712.pdf">some researchers</a> believe hiccups are a mechanism to help prepare the lungs for breathing shortly after birth. </p>
<h2>How long will they last? And what can you do about them?</h2>
<p>An attack of hiccups that lasts less than 48 hours is generally <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">unconcerning</a>. Such an attack usually ends by itself. </p>
<p>Where it doesn’t resolve by itself, there are <a href="https://pubmed.ncbi.nlm.nih.gov/25055206/">ways</a> to suppress the reflex arc. The <a href="https://my.clevelandclinic.org/health/treatments/23209-valsalva-maneuver">Valsalva manoeuvre</a>, consuming ice-cold drinks and gentle eyeball pressure are thought to increase the activity of a long nerve (vagus) to the brain. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=856&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=856&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=856&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1076&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1076&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516877/original/file-20230322-309-cryuhg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1076&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Manoeuvres such as rebreathing into a paper or plastic bag work by <a href="https://pubmed.ncbi.nlm.nih.gov/29729130/">increasing the carbon dioxide concentration</a> in the blood. This <a href="https://pubmed.ncbi.nlm.nih.gov/22523721/">helps to suppress</a> the movements of the muscles associated with hiccups. However, rebreathing carries a small but serious risk of <a href="https://www.sciencedirect.com/science/article/abs/pii/S0196064489805153">heart attack</a> so should only be performed under medical supervision. </p>
<p>However there is <a href="https://www.tandfonline.com/doi/full/10.1080/0964704X.2019.1708161">very limited evidence</a> to show these manoeuvres and interventions work. </p>
<h2>When should we get worried about hiccups?</h2>
<p>If hiccups last <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3006663/">longer than two days</a>, they are called persistent hiccups. If they <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3006663/">last beyond two months</a> they are known as intractable hiccups.
Persistent and intractable hiccups, known collectively as chronic hiccups, can be quite distressing and may signify a serious underlying cause, so it’s important to see your doctor. </p>
<p>People with chronic hiccups will undergo a comprehensive investigation. Their medical history will often give valuable clues to triggers. Certain medications such as anti-epileptic drugs, alcohol, smoking and recreational drug use are <a href="https://pubmed.ncbi.nlm.nih.gov/28759492/">all associated</a> with hiccups. </p>
<p>As organs in the chest and abdomen are involved in the reflex arc, <a href="https://pubmed.ncbi.nlm.nih.gov/28759492/">investigations of these organs</a> such as lung imaging or upper endoscopy (where a tube with a tiny camera is inserted into the throat to view the upper digestive tract), may be required.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/20427147/">One study</a> from France found 80% of patients with chronic hiccups had abnormalities in their oesophagus and stomach, with reflux disease being the most common finding. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-gastric-reflux-18791">Explainer: what is gastric reflux?</a>
</strong>
</em>
</p>
<hr>
<p>Your clinician will also inspect your <a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">ear, nose and throat</a>, as irritation of the ear by a foreign body or infection of the throat can be triggers for hiccups. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/26307025/">Imaging of the brain</a> may be necessary, especially if there are concerning signs such as changes in speech and weakness of facial and limb muscles. </p>
<figure class="align-center ">
<img alt="Iced water on a table" src="https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513103/original/file-20230302-28-399hx6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Drinking ice cold water helps some people.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/xUmStcovVvY">Giorgio Trovato/Unsplash</a></span>
</figcaption>
</figure>
<h2>How are chronic hiccups treated?</h2>
<p>After a thorough investigation, the underlying cause should be treated, where possible. </p>
<p>People suffering from hiccups often have problems with <a href="https://pubmed.ncbi.nlm.nih.gov/20427147/">gastric reflux</a>, so treatment may include a short course of anti-reflux medication. </p>
<p>Other medications with a strong evidence base that are used to treat hiccups include the anti-nausea drug <a href="https://pubmed.ncbi.nlm.nih.gov/25069531/">metoclopramide</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/25052238/">baclofen</a>, which is used to treat muscle spasticity (excessive tightness or tone).</p>
<p>There is <a href="https://pubmed.ncbi.nlm.nih.gov/28759492/">emerging evidence</a> that gabapentin, used to treat seizures, may also be effective for hiccups. </p>
<h2>What treatments might we see in future?</h2>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/35760460/">Researchers</a> have recently developed a rigid drinking tube with an inlet valve that requires active suction effort to draw water from a cup into the mouth. This tube has been called <a href="https://hiccaway.com/">forced inspiratory suction and swallow tool</a>, or FISST. </p>
<p>FISST is thought to stop the hiccup reflex arc by stimulating the sensory nerves to cause contraction of the diaphragm and glottis. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1408954166714667019"}"></div></p>
<p>In <a href="https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2781196">one study</a>, of the 249 participants who trialled FISST, just over 90% reported results better than home remedies. </p>
<p>However, the FISST research so far hasn’t compared it to a control group who didn’t receive the treatment, so it’s unclear how much more effective it is than a placebo, or dummy version. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-we-burp-137493">Curious Kids: why do we burp?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/196557/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vincent Ho does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There are simple ways to alleviate regular hiccups – and treatments for when they persist.Vincent Ho, Associate Professor and clinical academic gastroenterologist, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1999472023-03-10T13:40:22Z2023-03-10T13:40:22ZFrom grave robbing to giving your own body to science – a short history of where medical schools get cadavers<figure><img src="https://images.theconversation.com/files/514518/original/file-20230309-22-axut7p.jpg?ixlib=rb-1.1.0&rect=42%2C404%2C1903%2C1444&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">These Georgetown University medical students used donated cadavers in their anatomy class in 2011.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/liz-harkin-uses-a-running-tap-to-clean-out-a-human-heart-news-photo/145376204">Bill O'Leary/The Washington Post via Getty Images</a></span></figcaption></figure><p>In 1956, <a href="https://www.newspapers.com/clip/120516087/alma-merrick-helms-1958/">Alma Merrick Helms</a> announced that she was bound for Stanford University. But she would not be attending classes. Upon learning that there was a “special shortage of women’s bodies” for medical students, this semiretired actress had filled out forms to <a href="https://catalog.loc.gov/vwebv/search?searchCode=LCCN&searchArg=25011667&searchType=1&permalink=y">donate her corpse</a> to the medical college upon her death. </p>
<p>As <a href="https://history.utk.edu/people/susan-lawrence/">historians</a> <a href="https://history.wisc.edu/people/lederer-susan-e/">of medicine</a>, we had long been familiar with the tragic tales of 18th- and 19th-century grave robbing. Medical students had to snatch unearthed bodies if they wanted corpses to dissect. </p>
<p>But there was <a href="https://www.technologyreview.com/2022/10/12/1060924/donating-your-body-science-body-farm/#">little to no discussion of the thousands</a> of Americans in the 20th century who wanted an alternative to traditional burial – those men and women who gave their bodies to medical education and research.</p>
<p>So we decided to research this especially physical form of philanthropy: people who <a href="http://doi.org/10.1353/bhm.2022.0020">literally give themselves away</a>. We are now writing a book on this topic.</p>
<h2>Grave robbing and executed criminals</h2>
<p>As more and <a href="https://www.press.jhu.edu/books/title/1862/learning-heal">more medical schools opened</a> before the Civil War, the profession faced a dilemma. Doctors needed to cut open dead bodies to learn anatomy because no one wanted to be operated on by a surgeon who had only been trained by studying books.</p>
<p>But <a href="https://yalebooks.yale.edu/book/9780300078688/the-sacred-remains/">for most Americans</a>, cutting up dead human beings was sacrilegious, disrespectful and disgusting. </p>
<p>According to the ethos of the day, only criminals deserved such a fate after death, and judges intensified murderers’ death sentences by adding the <a href="https://www.jstor.org/stable/20092326?seq=1">insult of dissection</a> after their executions. As in life, the <a href="http://www.beacon.org/The-Price-for-Their-Pound-of-Flesh-P1227.aspx">bodies of enslaved people were also exploited in death</a>, either consigned for dissection by their masters or robbed from their graves.</p>
<p>Yet there were never enough legally available bodies, so <a href="https://www.smithsonianmag.com/history/in-need-cadavers-19th-century-medical-students-raided-baltimores-graves-180970629/">grave robbing flourished</a>. </p>
<h2>The unclaimed poor</h2>
<p>To meet the medical professon’s growing demand for cadavers, Massachusetts enacted the <a href="https://collections.countway.harvard.edu/onview/exhibits/show/nature-of-every-member">first anatomy law</a>. This measure, passed in 1831, made the bodies of the unclaimed poor available for dissection in medical schools and hospitals. </p>
<p>With more medical schools opening and grave-robbing scandals pushing politicians to act, similar legislation eventually took effect across the United States.</p>
<p>One of the most visible incidents occurred when the body of former Rep. John Scott Harrison, both the son and the father of U.S. presidents, involuntarily <a href="https://www.mentalfloss.com/article/64221/body-snatching-horror-john-scott-harrison">turned up on an Ohio dissecting table in 1878</a>.</p>
<p>In many states, kin and friends could claim a body that would otherwise be destined for dissection, but only if they could pay burial costs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Women embrace each other at a grave strewn with flowers." src="https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=439&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=439&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=439&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=551&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=551&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514279/original/file-20230308-26-wolhb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=551&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Monuments to honor those who have donated their bodies to science like this one can offer opportunities for their loved ones to mourn and remember them.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/bodies-photos-by-michael-williamson-neg-6-19-06-burial-news-photo/97103197">Michael Williamson/The Washington Post via Getty Images</a></span>
</figcaption>
</figure>
<h2>Donated bodies</h2>
<p>Yet not everyone shared the horror at the very idea of being dissected.</p>
<p>By the late 19th century a growing number of Americans were willing to <a href="http://doi.org/10.1353/bhm.2022.0020">let medical students cut up their bodies</a> before eventual burial or cremation. It did not apparently frighten or disgust them. </p>
<p>Doctors volunteered, but so did nurses, store owners, actors, academics, factory workers and freethinkers – even prisoners about to be executed. Some were people who simply sought to avoid funeral expenses. </p>
<p>Other Americans hoped that doctors would use their bodies to research their diseases, while others wanted to enable “medical science to enlarge its knowledge for the <a href="https://www.newspapers.com/clip/103849794/1901-young-george/">good of mankind</a>,” as George Young, a former wagon-maker, requested before he died in 1901.</p>
<h2>Cornea transplants</h2>
<p>By the late 1930s, <a href="https://www.google.com/books/edition/Flesh_and_Blood/6Q4TDAAAQBAJ?hl=en&gbpv=1&dq=susan+lederer+%22dawn+society%22&pg=PA199&printsec=frontcover">advances in cornea transplant surgery</a> made it possible for Americans to gift their eyes to restore the sight of blind and visually impaired men, women and children.</p>
<p>Along with <a href="https://www.smithsonianmag.com/science-nature/again-and-again-in-world-war-ii-blood-made-the-difference-1-32174495/">World War II blood drives</a>, heartwarming stories about corneal transplants spread a radically new understanding of corporeal generosity. </p>
<p>As efforts to attract donors who would <a href="https://doi.org/10.1016/0039-6257(82)90151-5">pledge their eyes at death spread in the 1940s</a> and early 1950s, so too did a new problem for anatomists: a decline in the number of unclaimed bodies. </p>
<p>Anatomists blamed a <a href="https://archive.org/details/humandissectioni00lassrich/page/n269/mode/2up">host of factors</a>: <a href="https://www.loc.gov/classroom-materials/united-states-history-primary-source-timeline/post-war-united-states-1945-1968/overview/">rising prosperity in the postwar years</a>; new laws that allowed county, city and state welfare departments to bury the unclaimed; veterans’ death benefits; Social Security death benefits; and outreach by church groups and fraternal orders to take care of their poverty-stricken members. </p>
<h2>Dear Abby and Reader’s Digest</h2>
<p>By the mid-1950s concerns arose about <a href="https://archive.org/details/humandissectioni00lassrich/page/n267/mode/2up">cadaver shortages for anatomy classes</a>. But media coverage of people who had chosen to donate their bodies started to sway others to follow suit. Good examples include a <a href="https://worldcat.org/identities/lccn-n81-103052/">Dear Abby</a> advice column published in 1958 and a <a href="https://bookriot.com/history-of-readers-digest/">Reader’s Digest</a> article in 1961.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&rect=0%2C633%2C1429%2C1105&q=45&auto=format&w=1000&fit=clip"><img alt="Black and white photo of a woman in a suit sitting in a mausoleum" src="https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&rect=0%2C633%2C1429%2C1105&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=860&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=860&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=860&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1081&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1081&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514276/original/file-20230308-626-l2rde3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1081&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In her exposé of the funeral industry’s problems, author Jessica Mitford endorsed donating bodies to science.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/author-jessica-mitford-sitting-in-a-mausoleum-in-sunset-news-photo/50439405">Ted Streshinsky/Getty Images</a></span>
</figcaption>
</figure>
<p>In 1962, Unitarian advocate Ernest Morgan published “<a href="https://search.library.wisc.edu/catalog/999526260202121">A Manual of Simple Burial</a>,” which promoted memorial services as alternatives to lavish funerals. He included a directory of medical schools and dental schools that accepted whole-body donations.</p>
<p>Journalist Jessica Mitford, in her wildly popular 1963 book that condemned the funeral industry, “<a href="https://archive.org/details/americanwayofdeamitf00mitf">The American Way of Death</a>,” also endorsed that practice. She helped make giving your body to science a respectable, even noble, alternative to expensive conventional burials.</p>
<p>In the early 1960s, <a href="https://www.nejm.org/doi/full/10.1056/NEJM196201252660406">Protestant, Catholic and Reform Jewish</a> leaders also came out in favor of donating bodies to science. </p>
<p>By the late 1960s and early 1970s, some anatomy departments began to organize <a href="https://www.newspapers.com/image/305525888/?terms=%22Their%20service%20to%20mankind%20continued%20after%20death%22&match=1">memorial services</a> to acknowledge donors and provide some closure for their loved ones.</p>
<p>Word of such efforts further encouraged whole-body donation. </p>
<h2>Letters of encouragement</h2>
<p>We reviewed <a href="http://doi.org/10.1353/bhm.2022.0020">dozens of unpublished letters</a> to and from donors in the 1950s to the early 1970s, in which anatomy professors encouraged potential whole-body donors to see themselves as heroically giving to medical science. Early donors frequently expressed this altruistic vision, wanting their mortal shells to participate in advancing knowledge. </p>
<p>By the mid-1980s, most medical and dental schools relied on donated bodies to teach anatomy, although a <a href="https://doi.org/10.1097%2FACM.0000000000002227">few unclaimed bodies</a> still make their way today to medical schools. <a href="https://doi.org/10.1111%2Fjoa.12056">Technology has revolutionized</a> anatomy teaching, as with the National Library of Medicine’s <a href="https://www.nlm.nih.gov/research/visible/visible_human.html">Visible Human Project</a>, but <a href="https://doi.org/10.1002/ase.1649">cadavers are still needed</a>.</p>
<p>Images and models cannot replace hands-on experience with the human body. </p>
<p>Where many Americans once <a href="https://www.newspapers.com/clip/120453623/her-scalpel-in-hand/">regarded medical students as “butchers</a>” for exploiting their beloved dead, contemporary students honor what some of these future doctors call their “<a href="https://doi.org/10.7812/tpp/07-145">first patients</a>” for the precious gift they have been given.</p><img src="https://counter.theconversation.com/content/199947/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>This particularly physical kind of philanthropy caught on in the mid-20th century.Susan Lawrence, Profesor of History, University of TennesseeSusan E. Lederer, Professor of Medical History and Bioethics, University of Wisconsin-MadisonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1970112023-01-22T19:02:35Z2023-01-22T19:02:35ZWe can still see these 5 traces of ancestor species in all human bodies today<figure><img src="https://images.theconversation.com/files/504835/original/file-20230117-3073-b5tm5x.jpg?ixlib=rb-1.1.0&rect=242%2C26%2C5416%2C3332&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/ufVCWjfFh5Q">Elia Pellegrini/Unsplash</a></span></figcaption></figure><p>Many of us are returning to work or school after spending time with relatives over the summer period. Sometimes we can be left wondering how on earth we are related to some of these people with whom we seemingly have nothing in common (especially with a particularly annoying relative). </p>
<p>However, in evolutionary terms, we all share ancestors if we go far enough back in time. This means many features in our bodies stretch back thousands or even millions of years in our great family tree of life. </p>
<p>In biology, the term “<a href="https://en.wikipedia.org/wiki/Homology_(biology)">homology</a>” relates to the similarity of a structure based on descent from a shared common ancestor. Think of the similarities of a human hand, a bat wing and a whale flipper. These all have specialist functions, but the underlying body plan of the bones remains the same.</p>
<figure class="align-center ">
<img alt="A graphic showing three shared bone structures across humans, dogs, birds and whales." src="https://images.theconversation.com/files/505484/original/file-20230119-26-ldvf9z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505484/original/file-20230119-26-ldvf9z.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=514&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505484/original/file-20230119-26-ldvf9z.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=514&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505484/original/file-20230119-26-ldvf9z.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=514&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505484/original/file-20230119-26-ldvf9z.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=647&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505484/original/file-20230119-26-ldvf9z.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=647&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505484/original/file-20230119-26-ldvf9z.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=647&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Волков Владислав Петрович/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>This differs from “analogous” structures, such as wings in insects and birds. Although they serve a similar function, the wings of a dragonfly and the wings of a parrot have arisen independently, and don’t share the same evolutionary origin.</p>
<p>Here are five examples of ancient traits you might be surprised to learn are still seen in humans today. </p>
<h2>One step ahead</h2>
<p>What makes us human? This question has plagued scientists and scholars for centuries. Today it seems relatively straightforward to tell who is a human and who is not, but looking through the fossil record, things very quickly become less clear. </p>
<p>Does humanity begin with the origins of our own species, <em>Homo sapiens</em>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6736881/">from 300,000 years ago</a>? Or should we stretch things back more than three million years to ancestors such as “<a href="https://en.wikipedia.org/wiki/Lucy_(Australopithecus)">Lucy” (<em>Australopithecus afarensis</em>)</a> from eastern Africa? Or even further back to our split from the other great apes? </p>
<p>Whatever line you draw in the sand to pinpoint the birth of humanity, one thing is certain. The act of habitually walking around on two legs, known as “bipedalism”, was one of our ancestors’ greatest steps. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two naked feet taking a step on a blue gait measuring plate in a laboratory" src="https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504834/original/file-20230117-14-9008f2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">It’s hard to overestimate the importance of bipedalism in human evolution.</span>
<span class="attribution"><span class="source">Microgen/Shutterstock</span></span>
</figcaption>
</figure>
<p>Almost every part of our skeleton was affected by the switch from walking on all fours to standing upright. These adaptations include the alignment and size of the foot bones, hip bones, knees, legs, and vertebral column. </p>
<p>Importantly, we know from fossil skulls that rapid increases in our brain size <a href="https://www.science.org/doi/abs/10.1126/science.809842">occurred shortly after we started walking upright</a>. This required changes to the pelvis to allow for our larger-brained babies to fit through a widened birth canal. </p>
<p>Our broadened pelvis (sometimes called iliac flaring) is a homologous feature <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2014.0063">shared with several lineages of early fossil humans</a>, as well as all those living today. </p>
<p>Those big brains of ours then fuelled an explosion of art, culture and language, important concepts when considering what makes us human. </p>
<h2>A hole in your head</h2>
<p>In addition to your eyeballs sitting in their orbits, you may be surprised to learn that you have other large holes (known as fenestrae) in your skull.</p>
<p>A single window is found on each side of the human skull, uniting us with our <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/spp2.1316">shared common ancestors from over 300 million years ago</a>. </p>
<p>Animals with this single window in their skulls are known as <a href="https://en.wikipedia.org/wiki/Synapsid">synapsids</a>. The word means “fused arch”, referring to the bony arch found underneath the opening in the skull behind each eye. </p>
<p>Today all mammals, including humans, are synapsids (but reptiles and birds are not).</p>
<p>Other famous synapsids from prehistoric times include the often misidentified <a href="https://en.wikipedia.org/wiki/Dimetrodon"><em>Dimetrodon</em></a>. The sail-backed ancient reptile is commonly mistaken for a dinosaur. However, with its sprawling limbs and single temporal fenestra it instead belongs to a lineage sometimes referred to as “mammal-like reptiles”, although we prefer the more accurate term of synapsid. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Colourful illustration of a green, reptile-like animal with a large semi-circular fin across its entire back" src="https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504825/original/file-20230117-3073-lcg0m1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Artist’s impression of a Dimetrodon, a long-extinct animal that was not a dinosaur.</span>
<span class="attribution"><span class="source">David Roland/Shutterstock</span></span>
</figcaption>
</figure>
<h2>10 little fingers and 10 little toes</h2>
<p>I am typing this article on my computer using ten of my digits (fingers and thumbs; digits also refer to toes but mine don’t reach the keyboard).</p>
<p>This pattern of five digits in the human hand or foot, known as a “pentadactyl limb”, is found in most amphibians, reptiles, birds and mammals.</p>
<p>But fish don’t have fingers and toes, so when was it that digits first evolved? </p>
<p>A <a href="https://www.nature.com/articles/s41586-020-2100-8?from=article_link">recent study</a> by myself and colleagues actually described the first digits found preserved within a fish fin. We used powerful imaging methods to peer inside a 380-million-year-old fossil called <em>Elpistostege</em> from Quebec, Canada, to reveal the oldest fish fingers!</p>
<p>Somewhat surprisingly, the first fish to evolve digits still retained fin rays around them so these bones would not have been visible on the animal externally. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/uyUYKTBA91k?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The earliest tetrapods (four-limbed animals with a backbone that eventually moved out of water and onto land) “experimented” with the number of digits, sometimes being found with six, seven or eight of them. </p>
<p>These earliest tetrapods were likely still living in the water. It wasn’t until tetrapods became truly terrestrial that the five-digit limb arrived. This arrangement most likely arose as a practical solution <a href="http://www.prehistoric-wildlife.com/species/p/pederpes.html">to weight bearing on land</a>. </p>
<h2>Long in the tooth</h2>
<p>Does your mind wander when you brush your teeth? Well, have you ever considered how evolutionarily old your pearly whites are?</p>
<p>In 2022 a team of palaeontologists described isolated fossil fish teeth <a href="https://www.nature.com/articles/s41586-022-05166-2">from Silurian age rocks in Guizhou province, China</a>. This remarkable discovery pushed the minimum age of teeth back a further 14 million years from previous findings. This means our dentition now harks back to a whopping 439 million years ago. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a stone spiral with pointy edges set on a purple background" src="https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=572&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=572&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505485/original/file-20230119-19-gajnjf.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=572&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A fossil of a <em>Helicoprion bessonowi</em> tooth whorl from the Ural Mountains, Russia.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Helicoprion#/media/File:Spirale_dentaire_d'helicoprion.jpg">Citron/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>That new fish, a very early jawed vertebrate, was named <em>Qianodus duplicis</em> and is only known from isolated specialised teeth known as “whorls”. A tooth whorl is a bizarre row of teeth that curls in on itself in a spiral pattern (most famously present in the buzz-saw shark, <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2013.0057"><em>Helicoprion</em></a>). </p>
<p>Nevertheless, the teeth in the Chinese jawed fish have a number of features found in other modern jawed vertebrates, which highlight their relevance in understanding the evolution of our very own gnashers. Chomp on that! </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/hIqfRC8Nb64?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Grow a spine</h2>
<p>To “grow a spine” means to become emboldened and confident. The first animals to do just that must have surely been courageous to venture out into the perilous ancient seas 500 million years ago. </p>
<p>First, these worm-like animals evolved a “notochord” – a rod built of cartilage running along the back of the body. This enabled the attachment of segmented muscle blocks and a long tail extending beyond the anus. All animals with a notochord are called <a href="https://manoa.hawaii.edu/exploringourfluidearth/biological/invertebrates/phylum-chordata">chordates</a>, and includes everything from sea squirts to sea gulls, comprising more than 65,000 living species. </p>
<p>To get an idea of the first chordates, today we can look to animals such as the <a href="https://en.wikipedia.org/wiki/Lancelet">lancelet</a> (known as <em>Amphioxus</em> or <em>Branchiostoma</em>). Lancelets look a bit like tiny, primitive fishes without fins. They swim by undulating their body from side to side.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A semi-transparent looking fish with no fins on a dark background" src="https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=475&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=475&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=475&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=597&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=597&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504832/original/file-20230117-18-k69nqy.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=597&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Branchiostoma lanceolatum, a type of lancelet.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Lancelet#/media/File:Branchiostoma_lanceolatum.jpg">Hans Hillewaert/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Next come those with well organised heads (craniates), and those in which the notochord is replaced by a backbone in adults (vertebrates).</p>
<p>A backbone is built of individual segmented bones (vertebrae) which fit together in a specific interlocking pattern. We have a few tantalising fossils representing the earliest known examples of vertebrates, such as <a href="https://www.nature.com/articles/nature13414"><em>Metaspriggina</em></a> known from Canada, or <a href="https://www.nature.com/articles/nature01264"><em>Haikouichthys</em></a> from China in rocks more than 500 million years old.</p>
<p>So, whether it be your large brain and broad pelvis from walking around upright, skull with a single opening and bony arch, your fingers, toes, teeth or spinal cord, we humans share many ancient features in our bodies.</p>
<p>And so, <a href="https://allpoetry.com/Human-Family">in the words of the poet and activist Maya Angelou</a>, it may be worth remembering that we are more alike than we are unalike.</p><img src="https://counter.theconversation.com/content/197011/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice Clement receives funding from the Australian Research Council.</span></em></p>If we go far enough back in time, we all share an ancestor. And some of the features found in our bones and bodies today are a testament to that.Alice Clement, Research Associate in the College of Science and Engineering, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1926962022-12-29T11:34:27Z2022-12-29T11:34:27ZCurious Kids: do all animals have belly buttons?<figure><img src="https://images.theconversation.com/files/498236/original/file-20221130-24-drshy4.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5607%2C3724&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/toddler-playing-red-cat-on-white-221784694">Alena Ozerova/Shutterstock</a></span></figcaption></figure><p><strong>Do live-born lizards have belly buttons, and do live-born reptiles have an umbilical cord? – Gaelle, aged 12, Bristol, UK</strong></p>
<p>What an interesting question! </p>
<p>A belly button or tummy button is technically known as a <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/umbilicus">navel or umbilicus</a>.</p>
<p>Humans have belly buttons because before we are born, we are connected to our mothers via an umbilical cord. This is a tube that delivers nourishment to the unborn baby, known as an embryo, and removes waste. It runs from the placenta – an organ in the mother that provides a source of food and oxygen – to the tummy of the embryo. </p>
<p>Once a baby is born, it can get nourishment such as milk through its mouth, and the umbilical cord is no longer needed. The umbilical cord shrivels up and drops off after a few weeks. So, a belly button is basically a scar from where the umbilical cord used to attach to the baby’s tummy.</p>
<p>Humans are part of the group of animals called mammals, and other mammal babies develop inside their mother in the same way, getting nourishment from the placenta via an umbilical cord. </p>
<figure class="align-center ">
<img alt="Baby orangutan" src="https://images.theconversation.com/files/498235/original/file-20221130-16-zp43wv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498235/original/file-20221130-16-zp43wv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=669&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498235/original/file-20221130-16-zp43wv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=669&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498235/original/file-20221130-16-zp43wv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=669&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498235/original/file-20221130-16-zp43wv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=841&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498235/original/file-20221130-16-zp43wv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=841&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498235/original/file-20221130-16-zp43wv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=841&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A baby orangutan showing its belly button.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-orangutan-after-square-meal-cute-150031340">olga_gl/Shutterstock</a></span>
</figcaption>
</figure>
<p>Belly buttons are quite large in humans, so they are pretty obvious. They are also visible in large mammals such as dolphins, orangutans and whales. Smaller mammals like cats, dogs and mice also have them, but the scars do not form large holes and they are often covered by hair or fur.</p>
<p>Other animal babies develop in different ways, though. Animals are actually separated into three groups, depending on how the embryos develop.</p>
<p>The first type is the one we have already talked about – when the embryo develops inside the mother and gets the food and oxygen it needs from the placenta. </p>
<p>The second type is animals that lay eggs. These animals, including reptiles, birds, amphibians and some mammals, don’t have a placenta to provide food for their babies. So, do they have a belly button too?</p>
<h2>Animals that lay eggs</h2>
<p>Animals that develop in eggs, rather than in a womb, still need food. But, instead of getting this from the mother, the food is present in the egg in a special area known as the yolk sac. This is the yellow bit that you see in the middle of a fried egg. Don’t worry, there are no babies in the eggs that you eat – they are unfertilised, meaning that they wouldn’t ever develop into babies. </p>
<p>The embryos in fertilised eggs aren’t able to drink the nutritious yolk through their mouths, in the same way that human embryos can’t drink until they are born. Instead, the embryos inside the eggs are attached to the yolk sac by a smaller feeding tube called the yolk stalk that goes to the <a href="https://www.birdspot.co.uk/bird-reproduction/anatomy-of-an-egg">tummy of the embryo</a>. </p>
<figure class="align-center ">
<img alt="Chicks hatching from eggs" src="https://images.theconversation.com/files/498237/original/file-20221130-11-xkoop2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498237/original/file-20221130-11-xkoop2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498237/original/file-20221130-11-xkoop2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498237/original/file-20221130-11-xkoop2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498237/original/file-20221130-11-xkoop2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498237/original/file-20221130-11-xkoop2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498237/original/file-20221130-11-xkoop2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Animals that come from eggs have belly buttons too.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/newborn-chicks-orange-communicate-each-other-580749094">Irina Kozorog/Shutterstock</a></span>
</figcaption>
</figure>
<p>The yolk stalk is similar to the umbilical cord, and it also dries up once the baby hatches as it is no longer needed. So, yes, animals that come from eggs do have a belly button scar, but it is usually so tiny that you would have difficulty seeing it.</p>
<p>But what about reptiles like lizards or snakes? They don’t have a placenta, like mammals, but they often don’t lay eggs. They are in the third group of animals.</p>
<h2>Ovoviviparous animals</h2>
<p>For these animals, the embryo develops inside an egg, but the egg stays inside the mother. These animals are called <a href="https://animalia.bio/ovoviviparous?page=1">ovoviviparous</a> animals. Sometimes the mother lays the eggs just before the babies are born, which is what the duck-billed platypus, an Australian mammal, does. Often, the eggs hatch inside the mother, so she gives birth to live-born babies. This is how some sharks and rays are born. </p>
<p>Reptiles like snakes or lizards are often ovoviviparous. Although they are live-born, they have not been attached to their mother via an umbilical cord. Instead, they have received nourishment through the yolk sac, via the yolk stalk. </p>
<p>So, yes – all animals have a belly button. Even dinosaurs had belly buttons! Recently, a fossil of a relative of triceratops was <a href="https://www.sciencealert.com/yes-dinosaurs-had-belly-buttons-sort-of-and-we-ve-now-seen-one-in-a-fossil">found with a belly button</a> scar very similar to the scars found on modern-day alligators. </p>
<p>The animals that have been attached to a mother through an umbilical cord, though, generally have a much larger belly button than those that have been attached to an egg yolk via an egg stalk.</p><img src="https://counter.theconversation.com/content/192696/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Louise Gentle works for Nottingham Trent University. </span></em></p>Some animals have belly buttons that are easy to see, but others have ones that are more difficult to spot.Louise Gentle, Principal Lecturer in Wildlife Conservation, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1965532022-12-14T03:29:05Z2022-12-14T03:29:05ZSnakes have clitorises<figure><img src="https://images.theconversation.com/files/500911/original/file-20221214-14-cj88o9.jpeg?ixlib=rb-1.1.0&rect=17%2C0%2C1904%2C1260&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Luke Allen</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Snakes have clitorises – and we have given a full anatomical description of them for the first time.</p>
<p>In <a href="https://doi.org/10.1098/rspb.2022.1702">research</a> published in Proceedings of the Royal Society B, we describe the size and shape of the snake clitoris (or hemiclitores) across nine species. </p>
<p>We also closely studied the cellular makeup of the clitoris in Australian death adders, finding it to be composed of erectile tissue and bundles of nerves.</p>
<p>The discovery of what appears to be a functional clitoris offers a new perspective on snake courtship and mating. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-sex-life-aquatic-how-moving-from-land-to-water-led-to-the-surprisingly-touchy-courtship-of-sea-snakes-159431">The sex life aquatic: how moving from land to water led to the surprisingly touchy courtship of sea snakes</a>
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</em>
</p>
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<h2>Finding the snake clitoris</h2>
<p>As part of her PhD research, our student Megan Folwell at the University of Adelaide had been dissecting snake specimens in museums. She came across a heart-shaped structure in the female tail, nestled between two scent glands, that she thought was the clitoris (or the hemiclitores, as it is called in snakes) and showed me.</p>
<p>I wasn’t sure what we were looking at, so we got in touch with Patricia Brennan at Mount Holyoke College in the US, who is an expert in how genitals have evolved in vertebrates. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An animation showing a wireframe drawing of the lower half of a snake's body with the clitoris highlighted." src="https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=323&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=323&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=323&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=406&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=406&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500876/original/file-20221213-151-bqi4g7.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=406&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The snake clitoris is a heart-shaped structure in the tail.</span>
<span class="attribution"><span class="source">Folwell et al</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>On closer inspection, we found it was a structure full of red blood cells and nerve tissue, as we would expect for erectile tissue. This suggests it is indeed the clitoris, and may swell and become stimulated during mating.</p>
<p>We went on to examine nine different species of snakes representing the major branches of snake evolution. All had a clitoris, though their sizes and shapes varied.</p>
<h2>Why didn’t we know about this already?</h2>
<p>Across all species, researchers have given female genitalia <a href="https://pubmed.ncbi.nlm.nih.gov/35353194/">a lot</a> <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001851">less attention</a> compared to its male counterpart. </p>
<p>What’s more, it’s hard to get a good look at snake genitalia. It’s all internal to the snake’s tail, for the most part, though the snake penis (or hemipenes) inflates for mating. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=627&fit=crop&dpr=1 600w, https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=627&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=627&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=788&fit=crop&dpr=1 754w, https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=788&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/500912/original/file-20221214-13-kq7mqq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=788&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The clitoris of an Australian death adder.</span>
<span class="attribution"><span class="source">Folwell et al.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>There has been quite a bit of research into the snake penis, but the snake clitoris has been missed.</p>
<p>While there are earlier reports, most actually referred to lizards, or mistakenly described the penis or scent glands, or featured only vague descriptions without anatomical references. Studies of species in which intersex individuals are relatively common heightened this confusion.</p>
<p>However, we have shown that the snake clitoris, although it shares its developmental origins with the penis, is very different from the penis – and our detailed anatomical description should help prevent this kind of confusion occurring in future.</p>
<h2>A crucial piece of anatomy</h2>
<p>In other species, we know the clitoris has <a href="https://linkinghub.elsevier.com/retrieve/articleSelectSinglePerm?Redirect=https%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0065345420300012%3Fvia%253Dihub&key=22f7498e0cabf6da1cbf5bbec791b299065c7bd7">important functions</a> in reproduction. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/all-female-mammals-have-a-clitoris-were-starting-to-work-out-what-that-means-for-their-sex-lives-114916">All female mammals have a clitoris – we're starting to work out what that means for their sex lives</a>
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<hr>
<p>Perhaps because many scientists assumed female snakes had no clitoris, and hence no capacity for arousal, it has generally been assumed that mating in snakes is largely a matter of males coercing females. </p>
<p>But a crucial piece of anatomy was missing from this conversation. Our discovery suggests female arousal – and something more like seduction – may play a role.</p>
<p>We still have a lot to learn. It may turn out that variation in the clitoris between species will be correlated with courtship and mating behaviours, and help us understand how females choose mates.</p><img src="https://counter.theconversation.com/content/196553/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jenna Crowe-Riddell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The first description of the snake clitoris may change what we think we know about mating and courtship among the slithering reptiles.Jenna Crowe-Riddell, Postdoctoral Researcher in Neuroecology, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.