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Forensic anthropology – the need for Australian standards

Given terrorism, natural disasters and other mass-fatality incidents seem to dominate news coverage, its never been more important to have an accurate and efficient means of identifying human remains…

Population-specific skeletons are of great value to forensic scientists. Didier Descouens

Given terrorism, natural disasters and other mass-fatality incidents seem to dominate news coverage, its never been more important to have an accurate and efficient means of identifying human remains.

Unfortunately, the people that do this job in Australia are being held back by a lack of sufficient, population-specific standards. This is a big issue, with real consequences.

My job (known as forensic anthropology) involves the application of standard scientific techniques to analyse human skeletal remains.

We do this to provide biological information that may assist in establishing personal identity which, among other things, helps provide closure to families.

The biological profile we create based on skeletal remains is known as an osteobiography, and it can be used to provide an estimation of sex, age, stature and ancestry in an unknown individual.

Additional responsibilities of the forensic anthropologist may include estimation of postmortem time and contributing to the pathologist’s determination of a possible cause (and manner) of death. This is done through the interpretation of peri-mortem skeletal pathology.

Generally, post-mortem interval (PMI) is established entomologically when there is still soft tissue and insect activity.

To estimate PMI based on bone condition (e.g. how much decomposition has occurred) the forensic anthropologist can look to the amount of weathering that has occurred.

But this is highly error-prone and influenced by many intrinsic and extrinsic factors: local environment (e.g. temperature and rainfall), bone density, whether the remains have been scavenged, and the cause of death, to name but a few.

Geographic variation in cranial shape. Franklin et al. 2010

The living

The role of the forensic anthropologist is continually evolving and now frequently involves identifying the living – ascertaining whether a person has reached a relevant age of criminal responsibility is one such example.

This is directly related to recent stories in the media about potentially-underage illegal migrants in Australian detention centres.

When people try to enter the country without proof-of-age documents, there needs to be a robust system in place to assess their age based on their relative skeletal maturity.

This should be done by examining the degree of dental development using statistical data from the individual’s own population (Indonesian in the recent cases).

Other existing standards use the skeletal development of the hand and wrist (based on American Caucasians from the 1930-40s) to estimate age. Unfortunately this method is very error-prone and unreliable in the absence of population-specific data.

Changes in the mandible show variation in the shape with age. Franklin et al. 2008

Standards

Standards – the data sets we employ – are vitally important to the forensic anthropologist. They are part of the toolkit we use to profile an unknown individual based on morphological variation in their skeletons.

From these we can estimate biological attributes in the skeleton – such as age, sex, stature and ancestry.

For example, a certain dental pattern is reflective of an eight-year-old with a possible range of two years either side.

Taking certain cranial measurements can provide an expected correct classification accuracy of 85% for estimating sex.

As already outlined, the forensic anthropological discipline in Western Australia (and Australia generally) is constrained by a relative paucity of these population-specific standards.

Collections of documented (known age, sex, stature and ancestry) skeletons – which are historically the main source of population-specific data – are largely unavailable.

This means we generally have little recourse but to apply established skeletal standards from populations that are not representative of modern Australians, but of North Americans and Europeans among others.

Measurements taken from CT scans (anterior views – blue dots are three-dimensional landmarks) are being used to formulate Australian-specific identification standards.

What we’re doing

The Forensic Anthropology Research Group at the Centre for Forensic Science (CFS) is currently developing novel forensic approaches for the analysis of human skeletal remains in both routine casework and disaster victim identification scenarios.

This casework might involve identifying skeletal remains found in a clandestine grave, scattered in a pine plantation, or any other way such remains might turn up.

Disaster victim identification might involve mass death scenarios such as car or plane crashes, natural disasters or acts of terrorism.

Our goal is to fortify the capabilities of forensic scientists in Australia through the development and implementation of a Human Identification Package (HIP) – a software tool designed to provide statistically quantified estimations of standard biological features, commonly used in the creation of an osteobiography.

To formulate the Australian standards we are currently using anonymised medical scans (see image above) and measurements from living individuals.

These offer a contemporary and reliable source of population-specific data from which skeletal standards for the estimation of age, sex and stature can be developed.

In a global era of crime, terrorism, natural disasters and other mass fatality incidents, the need for contemporary Australian standards, and novel approaches to identify unknown remains, are greatly overdue.

This is part four of The Conversation’s Forensics Australia series.

Read part one here. Read part two here. Read part three here.

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