Determination of sex with a discriminant analysis of new pelvic bone measurements: Part I.

The pelves of 100 black skeletons were measured on both sides for the following: (1) length from the superiormost aspect of the pubic symphysis to the nearest rim of the acetabulum (PS-A), (2) length from the highest point of the pubic tubercle to the nearest rim of the acetabulum (PT-A), (3) acetabular diameter (AD), (4) the vertical distance from the anterior aspect of the ischial tuberosity to the farthest rim of the acetabulum (IT-A), and (5) greatest femur head diameter. From these, three indices were derived: AD/PS-A (acetabulum/pubis index), AD/PT-A (acetabular diameter/pubic tubercle-acetabular rim index), and IT-A/PS-A (ischium-acetabulum height/pubic symphysis-acetabular rim index). The left AD/PS-A ratio and left IT-A height proved statistically to be of greatest discriminating value. Using these two variables, a discriminant function was derived which, followed by sorting with femur head diameter, accurately classified 97% of our sample. The acetabulum/pubis index alone with subsequent sorting by femur head diameter correctly assigned 96% of our sample. While this does not represent an improvement of predicatability over similar methods using the ischium/pubis index, measurements required for the acetabulum/pubis index are more easily defined and should, therefore, reduce the chance of observer error.