Sexual Dimorphism of the Lateral Angle of the Petrous Bone in Children: Growth Patterns and the Influence of Cranial Width

Background: The lateral angle of the internal acoustic meatus of the petrous bone is a sexually dimorphic feature used for sex determination, particularly in fragmented or cremated remains. However, studies show conflicting results regarding its accuracy, and the reasons for its dimorphism remain unclear. The aim of this study is to analyze sexual dimorphism in subadult individuals and to examine the association of the lateral angle with cranial breadth as an explanation for its sexual dimorphism, as well as interpopulation differences. Methods: We measured the lateral angle and biauricular breadth in 204 individuals (birth to 30 years) using CT scans from Austrian 19th-century anatomical collections and data from the New Mexico Decedent Image Database. Results: This study revealed that the sexual dimorphism of the lateral angle and cranial dimensions manifests during puberty, along with a strong association between the lateral angle and the biauricular breadth. Additionally, this study noted interpopulation variability in cranial breadth, with different levels of sexual dimorphism observed across diverse populations. Conclusions: The findings offer a potential explanation for the observed variability in lateral angle measurements across studies and the limitations of universal cut-off points as a sex-determination method in osteology.