New method of sex estimation through osteometric analysis of the lower limb for the Portuguese population

To reconstruct the identity of an individual, sex assessment is an essential step in the estimation of the biological profile of a skeleton. For that purpose, forensic anthropologists apply both morphological and metric methods based in skeletal elements. In 2000, Wasterlain used a sample from the Identified Skeletal Collection of the University of Coimbra (19th -20th centuries) to develop a method to estimate sex on the basis of the limb bones metrics. In the present study, a sample of 202 individuals (92 males and 110 females) from the 21st Century Identified Skeletal Collection (University of Coimbra) was used to revise the Wasterlain method to better suit the contemporary Portuguese population. In all, 22 measurements were performed in the femur, tibia, calcaneus, and talus. Although the Wasterlain method has shown satisfactory results, new cut-off points and discriminant functions were developed to promote accurate sex classifications in the contemporary Portuguese population. Regarding the cut-off points, the femoral vertical head diameter, the bilateral width of the tibia, the length of the calcaneus, and the maximum length of the talus presented the best results for sex estimation (89.8%, 88.0%, 85.6%, 85.9%, respectively). Discriminant functions presented correct classification percentages varying between 78.7% and 91.5% for femur, 83.7% and 93.0% for tibia, 84.9% and 86.6% for calcaneus, and 86.6% and 88.5% for talus. In sum, the new cut-off points and discriminant functions presented an overall good performance, constituting reliable methods to be applied in forensic cases involving individuals of Portuguese origin.