Anatomy of the mastoid triangle and morphometric sex differences

Abstract

Objective of the study: This study aimed to quantify the area of the mastoid triangle (MT) and assess potential morphometric differences between males and females.

Patients: The sample consisted of 244 dry human skulls, with biological sex known based on genetic analysis, collected from a medicolegal osteological database from Central-Western Brazil.

Materials and methods: The study was observational, analytical, and cross-sectional. The skulls were analyzed using Heron's equation to calculate the area of the MT. The landmarks connecting each of the sides of the triangle were: Porion (Po)>Mastoidale (Ma)>Asterion (Ast). Morphometric references were calculated and compared based on sex.

Results: The area of the MT was nearly 14% larger in males compared to females (p<0.05). The mean MT area for the right and left sides of males were 684.11±93.25mm² and 668.94±111.95mm², respectively. In females, the mean MT for the right and left sides were 588.93±91.09mm² and 582.88±102.98mm², respectively. Right and left side measurements were significantly different (p<0.05), except for Po-Ast (p=0.232).

Conclusion: Morphometric features regarding the MT were slightly different between males and females. Application of the MT as a dimorphic tool should be adjuvant. Moreover, this tool should be considered carefully, especially because the sex-based differences were statistically significant, but discrete between males and females.

Keywords: Mastoid process; Morphology; Morphometric; Skull; Temporal bone.