Multiple discriminant function analysis of sex and race in the postcranial skeleton

Terry Collection femora and innominates of 260 American Whites and Blacks (65 males and 65 females of each race) were analyzed by multiple discriminant function analysis. A stepwise procedure produced three optimal discriminant functions using 15 of our 32 measurements. These functions correctly identified 95% of the sample. The first two-one for sex and one for race-are statistically and biologically significant and form the basis of our analysis. The sexing function manifested both size and shape elements. Prominent among the former was joint size--acetabular diameter and epicondylar diameter of the femur. The shape elements included form of the greater sciatic notch and of the inferomedial aspect of the pubic body. The racing function highlighted a pattern of greater innominate dimensions, exclusive of the acetabular joint, in Whites. This was in contrast to the greater length of the Black femur. Overall, the function seems to express the established differences between the races in the ratio of lower limb length to torso length. While these functions have been applied successfully to forensic cases with confirmed identifications, questions regarding the breadth of applicability of discriminant functions make it desirable to validate our results on new material from the Terry and other collections.