Sex discrimination from the glenoid cavity in black South Africans: morphometric analysis of digital photographs

Given that skeletal material recovered from medicolegal contexts is often incomplete or damaged, forensic anthropologists need to have a variety of techniques at their disposal in order to correctly determine the sex of unidentified human remains. The purpose of the present study, therefore, was to produce practical standards for discriminating the sex of black South Africans using measurements of the glenoid cavity of the scapula. Standardized digital photographs of the left glenoid fossa were taken for 60 males and 60 females drawn from the Pretoria Bone Collection. An image analysis software program was then used to collect height, breadth, area, and perimeter data from each digital photograph. All four dimensions of the glenoid cavity were highly sexually dimorphic in this population group (p < 0.0001). Univariate logistic regression analysis yielded overall sex prediction success rates ranging from 88.3% for area of the glenoid fossa to 85.8% for glenoid fossa breadth. Multivariate procedures did not provide increased accuracy over those using only a single variable. Classification sex biases were below 5.0% for all equations. These results demonstrate that the analysis of glenoid cavity size provides a highly accurate method for discriminating the sex of black South Africans.