Course of the meatus acusticus internus as criterion for sex differentiation

The importance of features that allow the determination of an individual's gender even with skulls that have been largely destroyed is undisputed in archaeological and anthropological practice. Due to its extreme mechanical strength, the pars petrosa ossis temporalis is usually preserved in skulls and the sex dimorphisms of this skeletal part are therefore of particular significance. In the present study, we aimed at clarifying the controversial question whether the course of the meatus acusticus internus (M.a.i.) beneath the superior surface also reveals sex-specific differences. Using 410 forensically modern petrous portions, the course of the canal was examined and the respective angles determined using a specifically developed casting and cutting technique. The median values certainly reveal sex differences: the lateral angle on the male petrous portions is 10 degrees smaller than that of females; the medial angles on female petrous portions are approximately 5 degrees smaller than those of male skulls. Using discriminant analysis, approximately 66% of the specimens can be determined accurately.