A Virtual Anthropological Approach to the Study of Commingled Human Remains

Resolving commingling of human skeletal remains, where bones from more than one person are mixed up in an assemblage, is a complex issue in forensic anthropology. It is important to identify and return remains for legal, humanitarian, and related reasons, and commingling can prevent this from happening. Commingling results in a significant loss of the individualistic characteristics of the individuals present and can obstruct the personal identification process. As the issue of commingled remains is common enough in the criminal justice system, there is a need to devise adequate methods to sort mixed skeletal elements. One particularly understudied technique that has been used to sort commingled remains is joint articulation analysis. The underlying assumption when sorting commingled bones at joint articulations is that the joint surfaces within individuals will be more similar than those between individuals, although this assumption has never been fully tested. Therefore, this study aims to test this assumption and determine if commingled joints can be separated by using virtual anthropology (VA) methods. VA is a multidisciplinary and computer-assisted approach to studying the anatomical data of humans in three dimensions. Specifically, a 3D surface scanner will be used to create virtual models of the bones, which articulate at the atlanto-axial, sacroiliac, and first tarsometatarsal joints. These joints were selected because they have not yet been examined quantitatively, are all different shapes and sizes, and can join different segments of the body together (i.e., skull to neck). The shape of the articular surfaces will then be analyzed with deviation analysis, which creates a color-map deviation spectrum to indicate the overall differences in surface geometry between two specified virtual objects. These colors are accompanied by quantifiable values that can separate commingled remains as values of similarity within and between individuals. This research seeks to identify if there is greater shape variation found between the joints of commingled individuals compared to non-commingled individuals, while investigating which aspects of the joint surfaces are most similar or dissimilar. Further, the goals of this project include determining if a threshold value can be found to differentiate commingled and non-commingled joints and to rank the examined joints in order of ability to separate commingled remains based on these quantitative analyses. This research project intends to improve upon current separation techniques by incorporating a virtual approach that can reliably sort commingled remains and better inform our understanding of joint shape variation within and between individuals. Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14). CA/NCF