Sex estimation based on glabella morphology in contemporary Brazilian human skulls

Estimating sex from a dry skull depends on studying validated and specific traits. One such reference area exhibiting sexual dimorphism is the glabella, located on the frontal bone. This anatomical landmark is easily classified and shows promising results in sexual identification due to its magnitude variations between sexes. The present study is methodologically based on Walker’s approach, which visually analyzes cranial traits and scores them according to their morphology. This study aimed to investigate the sex estimation of dry skulls from Brazilian human skeletons for human identification through macroscopic analysis of the glabella. This analytical, quantitative, cross-sectional study utilized a sample of 471 skulls from both sexes, aged 25 years or older, belonging to the contemporary collection of the Center for Studies in Forensic Anthropology at the Faculty of Dentistry, University of Pernambuco (CEAF/FOP/UPE), Brazil. Data were recorded in an Excel spreadsheet and subsequently subjected to statistical analysis using IBM© SPSS (version 22.0). Initial observation of the skeletons excluded 52 (11.0%) due to age below 25 years, absence of a skull, or compromised glabella region, resulting in a final sample of 419 skulls. The mean age was 66.6 years, with a median of 67, a minimum of 25, and a maximum of 109 years. Regarding glabella types, score 2 showed the highest frequency (35.6%), while score 5 had the lowest percentage (7.9%). A statistically significant association was found between female sex and glabella scores 1 and 2. Also, individuals aged over 60 presented more glabella scores 1 and 2. The sex estimation accuracy for the sample was 76.1%, with females having a higher percentage of correct observations than males. The morphology of the glabella provides useful information for estimating sex in the biological profile. However, further studies on this morphological trait in other Brazilian osteological collections are encouraged to establish a national profile and contribute to human identification procedures in the country.