Nonmetric Sex Determination from the Distal and Posterior Humerus in Black and White South Africans

Abstract

: The successful identification of human skeletal remains relies on proven diagnostic techniques for sex determination. This research utilized 608 individuals from South Africa (420 men, 188 women) to conduct a blind nonmetric determination of sex from three features of the distal humerus: olecranon fossa shape, angle of the medial epicondyle, and trochlear extension. A scoring system between males and females was implemented, and the aggregate score of the three features determined the estimated sex of the skeletal element in question. With all features combined, black and white South Africans were categorized successfully as either male or female 75.5% (77% accuracy rate for females, 74% accuracy rate for males). This classification rate is lower than what was found in previous studies, but suggests that characteristics of the distal humerus are still quite valuable when estimating skeletal sex. More research is needed to assess reasons for the differential expression of these traits in different populations and to determine whether the method is nonpopulation specific.

Geometric morphometric assessment of sexually dimorphic characteristics of the distal humerus

“…Olecranon fossa shape and trochlear extension were also considered accurate predictors of sex when non-metric visual analysis was performed on each in isolation (Vance et al, 2011).…”

“…The first (EPI) view thus reflected the angle of the medial epicondyle, but also included the inferior view of the trochlea. The second view (OL) combined both the shape of the olecranon fossa and the trochlear symmetry, corresponding to the features as described by Vance et al (2011).…”

“…Morphological differences of both the distal and proximal humerus have also been studied, but to a lesser extent (Rogers, 1999;Rogers, 2009;Kranioti et al, 2009;Vance et al, 2011). Specifically the distal humerus is known to be dimorphic, and this is said to be due to differences in the carrying angle of the articulated humerus, radius and ulna (Grabiner, 1989;Fuss, 1991;Kingston, 2000).…”

“…Rogers (2009) then used the same methods to assign sex to juvenile and adolescent humeri, and found 80% accuracy in males and 82% accuracy in females. Vance et al (2011) used a large sample of 608 individuals from South Africa (420 males, 188 females) to test the accuracy of this method. They found it difficult to score trochlear constriction consistently, and discarded it from the list of characteristics because it gave confusing results.…”

Sex determination from femora in late antique sample from Eastern Adriatic coast (Salona necropolis)

“…Accuracy of the derived functions was determined by cross-validated classification method, in which each case is classified by the discriminant function calculated from all cases excluding that case. As 80% classification rate is considered useful for sex determination, only discriminant functions that met this criteria were considered relevant for this research (Vance et al 2011). We also reported eigenvalues, canonical correlations, and Wilk's lambda as indicator of the reliability of the discriminant functions.…”