Mastoid and Opisthion-Bimastoid Triangles for Sex Determination in a Brazilian Sample/Triangulos Mastoideo y Opistión-Bimastoideo para la Determinación del Sexo en una Muestra Brasileña

Human identification involving mutilation, advanced decomposition, and skeletonized materials is a challenge for professionals in forensic medicine and dentistry. This study was aimed at a morphometric analysis of the mastoid and bimastoid triangles to determine sex in a Brazilian population. The sample included 80 human skulls (34 females and 46 males; age: 18 to 60 years) from individuals with death certificates. Linear measurements (mm) of the mastoid process--right (n=3) and left (n=3)--and the opisthion-bimastoid (n=3) triangles were taken (digital caliper) by two previously trained researchers. Three cranial points--asterion, porion and process--were determined for the right and left mastoid triangle and three others--(1) opisthion and (2) right and (3) left mastoid--for the bimastoid triangle. Heron's formula was used to calculate the area of the triangles assessed. Data were submitted to the Shapiro-Wilk normality test, followed by the unpaired Student's t test or the Mann-Whitney U test, depending on the data distribution verified in the normality test (GraphPad Prism 5.01; p