Sex and age estimation utilizing the Mastoid, Bi-mastoid and Occipital triangles from three dimensional reconstructed models in subadults of a South African (KZN) Black population

Abstract

The mastoid, bi-mastoid and occipital triangles at the base of the skull are known to be good indicators of sexual dimorphism. However, few studies assess age and sex in the subadult group. Therefore, the aim was to determine the age and sex of the human crania from a South African (KZN) Black population utilizing the triangles of the base of the skull of individuals between 0 and 18 years. The sample consisted of 64 computed tomography (CT) scans (32 male and 32 female) between 0 and 18 years of age. Three-dimensional reconstructed images and CT images were analysed using SLICER 3D. The following linear parameters were measured: the mastoidale - porion; porion - asterion; mastoidale - asterion; left mastoidale - opisthion; right mastoidale - opisthion; right mastoidale - left mastoidale; left asterion - lambda; right asterion - lambda; left asterion - right asterion. The study found that the mastoid, bi-mastoid and occipital triangles are good indicators for sexual dimorphism between the ages of 0–18 years. However, the mean values of the total area were higher in males than females. When comparing laterality, the right side of the mastoid triangle was more significant than the left (p-value=0.016), with the length of the mastoidale-porion being the only significant linear measurement. Results show that the linear measurement mastoidale-porion is highly correlated to age, with mean values of r = 0.87 and 0.88 for the left and right sides, respectively. Age is a confounding factor in sexual dimorphism. Additionally, the mastoid triangle is more accurate in age estimation.

Keywords

• Age estimation
• Sex estimation
• Mastoid triangle
• Bi-mastoid triangle
• Occipital triangle