Technical note: Evaluating mandibular ramus flexure as a morphological indicator of sex

Described as a highly reliable method of sex identification, mandibular ram us flexure is a morphological trait expressed on the posterior border of th e ramus at the occlusal plane (Loth and Henneberg [1996] Am. J. Phys. Anthr opol. 99:473-485). In a blind test, 158 mandibles were examined for the pre sence of flexure as defined by Loth and Henneberg, resulting in 79.1% accur acy, which is well below the reported 91-99% accuracy. Twenty-five of these mandibles were assigned the ambiguous score of 0, an outcome of a +1 score for one side, and a -1 score for the other. Seventeen mandibles were exami ned twice to measure intraobserver error. Only 64.7% of the scores were dup licated in the second session, suggesting difficulty in consistent identifi cation of flexure. Low overall accuracy, an invalid scoring system, and hig h intraobserver error indicate that mandibular ramus flexure is an unreliab le technique for estimation of sex. (C) 2000 Wiley-Liss, Inc.