Bones Of The Knee Joint And Individual Features That can Be Used For Forensic Identification

This dissertation describes the normal osteology of the bones of the knee joint in correlation to the surrounding soft tissues. Traumatic and surgical modifications of the normal osteological features are also discussed in reference to their significance for anthropological analysis as well as for forensic identification. As a primary focus, a new method of racial determination from the distal femur is described in detail.

This new method involves the measurement of the intercondylar shelf in relation to the posterior shaft of the femur. The intercondylar shelf is a feature of the distal femur that shows significant difference between American Whites and Blacks. The intercondylar shelf is the "roof" of the intercondylar notch, and in lateral radiographs the posterior cortex of the femur and the intercondylar shelf can be seen as distinct lines of dense bone. The angle between the posterior shaft of the femur and intercondylar shelf can be easily defined and measured. For this study, lateral knee radiographs of 240 White and 183 Black subjects were measured. The White mean was 147 degrees (std. dev. 4.28) and the Black mean was 138 degrees (std. dev. 4.18). This difference is statistically significant (p < .0001) and yields a correct classification of 87%. The same measuring technique was performed as a blind test on radiographs of known skeletal material with similar results.

Variations in the intercondylar shelf angle are presumed to be independent of the size or shape of the femur. In addition, the measurement of this angle is not restricted or altered by arthritis in the notch or by trauma to the articular surfaces. Fragmentary femora can be measured. This is a non-invasive technique that can be used in forensic cases as well as archaeological cases where there are intact soft tissues.