Discriminant function sexing of the tibia.

The objective of the study was to test whether the shaft dimensions of the tibia were as sexually dimorphic as those of the femur and to develop a new sex determination technique from the tibia. Stepwise discriminant function subroutine based on a sample of 159 tibiae of blacks and whites of both sexes of the Terry Collection was employed for the study. Osteometric measurements included were the length, proximal and distal breadths, the circumference of the nutrient foramen and of the smallest shaft regions, and anteroposterior and transverse diameters at the nutrient foramen levels. The results indicated that in all dimensions proximal epiphyseal breadth and the minimum circumference were the variables selected by the stepwise function in blacks and that all but the transverse diameter participated in the function in whites. Average accuracy of sex determination was 87.3% for whites and 90.0% for blacks. For both races proximal epiphysis was a better indicator of sex differences than the remaining dimensions. While the study provided statistically reliable results sexual dimorphism was observed to be race dependent. This was especially true for blacks who provided higher prediction accuracy and more dimorphism than whites. Thus it was suggested that determination of sex required a consideration of not only growth related sex differences, and physical activity, but also the genetic (racial) nature of a population.