Measurements of the Foramen Magnum and Mandible in Relation to Sex Using CBCT

The purpose of this study was to evaluate pre-existing CBCT images of a large sample of adult females and males to provide data on foramen magnum and mandibular measures of sexual dimorphism for use as a reference sample in cases of establishing identity in unknown fragmentary skulls. The study group consisted of 161 adult patients. 3D images of the patients were assessed retrospectively. FM measurements were obtained from reformatted axial sections. Six mandibular measurements were taken. According to the results, the study identified four mandibular measurements as final predictors of sex which are as follows: the gonial angle (G-angle) and ramus length (Ramus-L), gonion-gnathion length (G-G-L) and bigonial breadth (BG-Br). It was found that the cross-validated grouped overall predictive accuracy was 83.2% for FM and mandible measurements. It could correctly identify males in 77.3% and females in 87.4% of the cases. To assess sexual dimorphism, the gonial angle and ramus, gonion-gnathion lengths, and bigonial breadth of the mandible and sagittal diameter of the FM may be used on CBCT images. © 2014 American Academy of Forensic Sciences.