Cremated human remains: is measurement of the lateral angle of the meatus acusticus internus a reliable method of sex determination?

The purpose of this study was to evaluate the lateral angle (LA) method-based on the measurement of the angle at which the internal acoustic canal opens up to the surface of the petrous bone-for sex determination in cremated skeletal remains of Italians. The sample consisted of 160 adult individuals of known age and sex who had recently died and were cremated in the crematorium of Ferrara (northern Italy). Several studies have demonstrated that the petrous portion of the temporal bone may be a valuable tool for sex diagnosis in unburned skeletal remains. Since petrous bones are usually preserved after cremation, this method could be of particular interest in the case of burned skeletal remains. The repeatability of intra- and inter-observer measurements was good. The results indicated that male and female lateral angles were significantly different but that the values did not differ among age-groups. There was no bilateral difference in LA. However, neither the 45° angle, proposed in earlier studies as the sectioning point for this variable from male and female data distributions, nor another angular value allowed satisfactory discrimination between the sexes in our sample. The influence of the "age" factor (about 82 % of females were of ≥ 75 years of age) on the results is critically discussed. The results of this study suggest that the LA method is not sufficiently reliable to assess the sex of elderly Italian individuals from their burned remains and thus should only be used in conjunction with other sexing techniques.