Sex determination in a Brazilian sample from cranial morphometric parameters - a preliminary study

Sex determination, which is based on the existence of dimorphism between specimens of the same species, plays an important role in the process of human identification. In the absence of pelvic elements, the skull appears to be the best sex indicator, and can also be submitted to quantitative or metric assessments. Eleven measurements were taken for this study, four in the sagittal plane and seven in the horizontal, in two groups of 186 skulls each, with 101 from males and 85 from females for those of the sagittal plane, and 100 and 86, respectively, for those concerning the horizontal, of subjects aged between 18 and 94 years at the time of death. The sample belongs to the Osteological and Tomographic Biobank Professor Doctor Eduardo Daruge of the Piracicaba Dental School of the University of Campinas. The aim of this research was to establish a reliable method to determine sex and elaborate mathematical prototypes capable of assisting in investigation or identification activities, in a preliminary study. Of the measures implemented (Lambda-Nasion, Lambda-Rhinion, Lambda-Nasospinale, Rhinion-Nasospinale, Zygomaxillare-Zygomaxillare, Lambda-Incisive Foramen, Lambda-Right Zygomaxillare, Lambda-Left Zygomaxillare, Basion-Incisive Foramen, Basion-Right Zygomaxillare and Basion-Left Zygomaxillare), only the Lambda-Nasospinale and Rhinion-Nasospinale in the sagittal plane, and the Zygomaxillare-Zygomaxillare and Lambda-Incisive Foramen in the horizontal plane, were significantly dimorphic. Two predictive mathematical models of sex were conceived for each pair of them: one of logistic regression and another of conditional inference trees, displaying accuracy rates of 78.5% and 77.42%, and of 68.28% and 72.04%, respectively. The authors concluded that there is the possibility to apply the aforementioned data in forensic anthropology as an auxiliary tool in investigation or identification tasks.