Identification of sex from metacarpals: effect of side asymmetry.

This study tests the effect of bilateral asymmetry on the success rate of correct prediction of sex based on osteometric dimensions of the second metacarpal, using a method proposed by Scheuer and Elington. A total of 351 bones from 179 individuals (47 documented as to age and sex), including 172 pairs, obtained from a 19th century cemetery were used to test the null hypothesis of no effect. A high success rate (> 90%) for correct identification was found for males irrespective of side, although the larger right second metacarpal was a significantly better predictor. Conversely, there was a much lower success rate for females irrespective of side (< 65%), although the smaller left metacarpal tended to give better results. The high success rate for males and low rate for females likely reflects the greater skeletal robustness of this historic sample relative to modern individuals. It is concluded that side asymmetry can have a significant effect on predictive efficiency for the Scheuer and Elkington model. As well, it is questionable whether the technique should be applied to non-industrial, that is, more skeletally robust, populations.