Lateral angle: A landmark-based method for the sex estimation in human cremated remains and application to an Austrian prehistoric sample

ObjectivesEstimating the sex of cremated human remains is difficult. The petrous bone frequently survives the cremation due to its density. Wahl observed the lateral angle to be sexually dimorphic in the 1980s. Previous studies showed various cut-off points to separate females from males, which are hardly replicable and difficult to apply. We want to test the Wahl method and compare it to a new landmark-based version.Materials and MethodsIn this study, we measured the lateral angle of 35 cremated petrous bones from late bronze age Austria using micro-CT scans. Technical errors of measurement were calculated for two different methods to intersect the internal acoustic meatus virtually in the midline (manual or landmark-based intersection). Furthermore, sex was estimated based on morphological features and metric measurements. This information was used in logistic regression modeling to define a cut-off point in our sample.ResultsThe technical errors of measurement suggested that a landmark-based method was more precise in comparison to a manual intersection which was much more intuitive. Inter- and intra-observer errors were low which improved reliability. The logistic regression model produced good results in our sample (p = 0.02, R2 = 0.38, accuracy = 0.8). The mean lateral angle was similar to studies which focused on prehistoric cremated petrous bones.DiscussionThe proposed landmark-based method was precise, quick, and could be easily applied, even by unexperienced researchers. The size of the lateral angle seemed to be population-specific but also dependent on the method applied. We recommend to use the proposed landmark-based method which is more precise.