Osteometric variation in the humerus: sexual dimorphism in South Africans

There has been a surge of research on forensic anthropology in South Africa. Differences between the populations of this country and others are demonstrated in many studies. Yet, many forensic osteometric techniques based on other populations are still in use. The purpose of the present study is to develop an osteometric sex determination technique using the humerus. The sample is composed of skeletons of 104 whites and 88 blacks from the Dart and Pretoria collections. Six humeral dimensions were initially analyzed using stepwise discriminant function statistics. Humeral head diameter, deltoid tuberosity circumference and epicondylar breadth were individually calculated in order to make the technique usable for fragmented remains. The results indicated that the head and epicondylar diameters are the best in whites to differentiate sexes from each other, while head diameter and maximum length are best in blacks. Accuracy of correct classification was as high as 96% in whites and 95% in blacks. Crossvalidation provided the same accuracy as the original classification. These accuracy percentages are as high as those expected from the femur and tibia. Posterior probability, which measures the percent affiliation of the sample with its original sex group, was also mostly 80% or better. South African collections are ideal for osteometric analysis, because they are still growing in numbers with cross-sectional representatives from the country.