The efficacy of sternal measurements for sex estimation in South African blacks

The correct assessment of sex from the human skeleton is of fundamental importance in forensic medicine and bioarchaeology. In South Africa, unidentified remains are often fragmentary, making it necessary to estimate sex from a variety of skeletal elements. The purpose of the present study was to evaluate the sex discriminating potential of the sternum in black South Africans using standard osteometric techniques. A sample of 123 males and 83 females drawn from the Raymond A. Dart Collection of Human Skeletons and the Pretoria Bone Collection was used. The results demonstrated that all eight sternal variables, including both dimensions and indices, were highly sexually dimorphic in this population. A stepwise discriminant function procedure, which selected corpus sterni length and manubrium width, correctly identified 86.4% of the individuals in the study sample. Additional multivariate discriminant equations incorporating dimensions for either the manubrium or corpus sterni yielded sex prediction rates of 80.6% and 84.5%, respectively. Sternal area, when used in isolation, produced the highest sex classification accuracy with 86.9% of specimens correctly assigned. The remaining single variable functions, which can be applied when well-preserved or complete sterna are not available for analysis, provided classification accuracies ranging from 68.4% to 83.5%. These classification results are comparable to those reported in previous investigations concerning sex estimation of black South Africans for other postcranial elements.