Sex Determination Using Mastoid Process Measurements in Brazilian Skulls

Abstract

SUMMARY:The mastoid process characteristics are of great utility in the diagnosis of sex. De Paiva & Segre (2003) described that sex diagnosis was possible based on the determination of the area of the triangle formed by the points porion, mastoidale, and asterion. The purpose of this study was to determine the existence of sexual dimorphism in the dimensions and the area of the mastoid triangle using statistical and discriminant function analysis. A total of 81 skulls of Brazilian individuals that were part of the Museum of the Federal University of Sao Paulo (UNIFESP) collection were used, with sex and ages known: 50 men and 31 women between 40 and 70 years of age (mean 51.58 years, SD 7.319). Most of the lineal dimensions and the calculated areas were higher in men than in women. Only the distance porion-mastoidale, the area of the right mastoid triangle and the total area, was higher and more significant in men with p < 0.01. The analysis of the discriminant function showed that the group of analyzed lineal dimensions presents a low discriminant capacity (Lambda of Wilks = 0.960, Canonical Correlation = 0.199); only porion-mastoidale allowed one to distinguish men's groups from women with a general accuracy of 64.2%, but with a high sensibility to classify men (93%) and a very low sensibility for women (17.7%). These results indicate that the determination of sex based on the dimensions of the mastoid triangle leads to underestimate the women, hence being of less utility in practice.

An Osteometric Study of Northern Indian Populations for Sexual Dimorphism in Craniofacial Region

“…Numerous anthropological traits and parameters have been investigated on different parts of the skull, in an effort to make the sex determination more easy, reliable, and consistent, e.g., cranium (16)(17)(18)(19)(20)(21)(22), mandible (7,(23)(24)(25)(26)(27), glabella (28), mastoid process (9,(29)(30)(31), occipital bone (32)(33)(34)(35).…”

Osteometric Estimation of Sex From Mastoid Triangle in Malaysian Population

“…The Saudi population came next after the present study based on the dimensions of mastoid triangle [11]. The dimensions of mastoid triangle and areas were comparable between Brazil, German, and Portuguese populations, which were smaller than those in our study [16,18,20]. Minimum dimensions of mastoid triangle and areas were found in the North Indians [28].…”

“…Although high classification accuracy was achieved, there was also high level of error in intra-and interobserver error measurements of the mastoid process [19]. Galdames et al (2008) studied the existence of sexual dimorphism in the dimensions and the area of mastoid triangle (AMT) using statistical and discriminant function analysis among 81 skulls of Brazilian individuals [20].…”

Análise da variabilidade métrica dos parâmetros de Antropologia Forense para estimativa do sexo de duas populações: escocesa e brasileira

“…O processo mastóide é uma estrutura óssea muito utilizada na literatura para estimativa do sexo, vários autores relataram resultados satisfatórios para analisar o dimorfismo sexual através desta estrutura 11,16,20,[207][208][209][210] . Os resultados deste estudo evidenciaram que todas variáveis relacionadas com o processo mastóide são estatisticamente significantes para diferenciação do sexo tanto na amostra brasileira quanto na amostra escocesa.…”