The impact of antimeric lower limb length asymmetry on adult stature estimation

Antimeric lower limb length asymmetry is frequently noted when measuring human skeletal remains. As lower limb bones are often used to estimate stature from unidentified remains, the forensic anthropologist who notes a disparity must then determine which lower limb bone or bones will produce an estimate that most accurately and precisely captures the unknown individual's stature. To help forensic anthropologists make informed decisions when remains exhibit lower limb antimeric asymmetry, left and right femora and fibulae maximum lengths were analyzed from 78 DPAA-identified individuals with measured statures. Results revealed 87.2% of individuals exhibited lower limb antimeric asymmetry, statistically significant differences between lower limb lengths, decreasing estimate accuracy when asymmetry increased, and that using a 99% prediction interval for disparities ≥5.0 mm nearly ensured documented measured stature would be captured. These findings were validated on independent samples of 20 adult males from the DPAA and 146 males and females from the Terry, Hamann-Todd, and Bass Collections. Preliminary results were largely supported; however, the accuracy reduction with increasing asymmetry observed in the DPAA data was not replicated. Based on these findings, we encourage bilateral measurement taking to identify lower limb antimeric asymmetry, caution against combining bone lengths from opposite sides, and recommend using a 99% prediction interval when lower limb length antimeric asymmetry is ≥5.0 mm and if using the FORDISC 3 Trotter M Stats database. When C Stats or F Stats are used, the prediction intervals associated with these less homogeneous databases are large enough to absorb error due to antimeric asymmetry.