Forensic Anthropology

The Wounds Time Does Not Heal

2025-01-02T10:18:52-05:00

The segregation and subsequent identification of skeletal remains from commingled contexts is a multifaceted and complicated process. Success or failure in this process relies heavily on training and experience, both during archaeological recovery and
anthropological analysis. This case study details the identification of a World War II service member associated with the Battle of Tarawa, drawing on multiple lines of evidence. Historical context, recovery, and analysis of the remains resulted in a misidentification of this individual in 1946. Present-day accounting efforts by the Defense POW/MIA Accounting Agency (DPAA), including the use of historical research, anthropological analysis, dental analysis, and DNA, were used to segregate and ultimately associate skeletal material recovered from three different recovery operations on Tarawa, leading to the correct identification of this service member in 2024.

Darrach Procedure

2025-03-12T11:10:52-04:00

A 62-year-old white male, whose remains were donated to Colorado Mesa University’s Forensic Investigation Research Station, presented with an unusual surgical procedure on the wrist. The distal end of the ulna was removed and a hole drilled through the stump. The medical history for this individual is minimal, but the technique is morphologically consistent with a Darrach procedure. A Darrach procedure is done to repair damage to the wrist joint by removing the distal end of the ulna. Modifications to this technique drill a hole in the ulnar stump as an anchor point for a tendon. Identification of a surgical procedure on unidentified skeletal remains may be useful to forensic specialists working to identify unknown remains.

rASUDAS2

2024-12-16T11:59:42-05:00

The web-based application rASUDAS, originally based on data from “The Anthropology of Modern Human Teeth,” has been refined since its inception in 2015, undergoing two significant updates. The initial alpha version included 12 crown and five root traits. The beta version expanded the list to 15 crown traits and six root traits. The latest iteration, rASUDAS2, has expanded to include four additional traits along with seven backup traits, allowing for flexibility in cases where certain primary traits, like shoveling on UI1, cannot be scored, so shoveling expression on UI2 is utilized. The Bayesian algorithm powering rASUDAS2 employs trait frequencies derived from archaeological finds. To evaluate its effectiveness with contemporary samples, rASUDAS2 was tasked with calculating posterior probabilities for samples of African and European descent. Utilizing between 12 and 25 traits, it assigns individuals to one of seven major biogeographic groups: Western Eurasia (WE), East Asia (EA), American Arctic (AA), non-Arctic America (n-AA), Southeast Asia (SEA), Australo-Melanesia (AM), and Sub-Saharan Africa (SSA). In a modern African sample (n = 159), the probability of classification into the Sub-Saharan African group was the highest at 68.6%, followed by Western Eurasian at 22.0%, with probabilities ranging from 0.6% to 4.4% for the other groups. Similarly, in a European-derived sample (n = 161), 75.2% were assigned to Western Eurasia and 13.0% to Sub-Saharan Africa, with the remaining 12% distributed among other groups. Approximately three out of four individuals from these regions could be accurately placed within their respective biogeographic groups. However, the likelihood of these individuals being assigned to any Asian-related group is low, at less than 10%. When assessing two mixed African and European samples, results indicated nearly equal percentages of affinity assignment, with around 40% for Sub-Saharan African and 30% for Western Eurasian.

Human Identification by Comparative Medical Radiography

2025-01-07T11:34:40-05:00

Personal identification is often an essential contribution of forensic anthropologists in medicolegal death investigations.
This research evaluated the accuracy and reliability of radiographic features of the lateral foot when used by professionals and graduate students in forensic anthropology for purposes of identification. A survey comprising five scenarios, each with one antemortem lateral foot radiograph and 20 postmortem lateral foot radiographs, was provided to participants (n = 35) from which they were asked to conclude an identification, an exclusion, or insufficient evidence. Four of the five scenarios included a postmortem match for the antemortem film, and one scenario did not have an associated match for the antemortem among the postmortems. The findings of this study indicate practitioners can reliably use lateral foot radiographs for positive identification or exclusion of tentative identities in comparative medical radiography casework with an overall correct classification rate (CCR) of 94.19% and a positive predictive value of 95.87%. Pairwise Mann–Whitney U tests for evaluator profession and evaluator case experience produced nonsignificant p-values (p ≥ 0.05) for all tests, suggesting identification accuracy is independent of observer profession and case experience.

Development and Validation of a Subadult Sex Estimation Method Using Pelvic Metrics

2025-03-12T10:35:36-04:00

The goal of this research is to explore the utility of pelvic interlandmark distances (ILDs) collected from partially and fully fused subadult innominates in sex estimation. The individuals were from the contemporary US subset of the Subadult Virtual Anthropology Database (SVAD) and between the ages of eight and 20 years (n = 364). Thirty-four pelvic landmarks were placed on 364 left innominates from which 11 standard ILDs were calculated using the X, Y, and Z coordinates. Linear discriminant function analyses using training (75%) and testing (25%) subsets were performed using the ILDs. An additional variable, the ILIS (triradiate cartilage) fusion score, was also incorporated as a predictor variable to capture biological maturity. Total correct sex classifications ranged from 90.88% to 97.78%; correct sex classification of females ranged from 94.29% to 100%, and correct classification of males ranged from 87.95% to 98.18%. Testing and training subsets were comparable, and there was minimal sex bias. Accuracies are remarkably similar to adult sex estimation methods and are stronger than pelvic morphological subadult sex methods currently published. Large samples enabled exploration of metric data to reveal the utility of pelvic ILDs for subadult sex estimation. These results are transformative to the field, as we can now confidently estimate sex, with a high level of accuracy, on individuals with actively fusing innominate or a completely fused innominate, which is younger than previously assumed.