Sexual Dimorphism in Mastoid Process Using Discriminant Function Analysis

 Determining sex from the human skeleton and its fragments has very high importance in anthropology, forensic medicine, and human osteology. Petrous temporal bone with the mastoid process is usually preserved in the case of burning, as it has compact structure with protected position at the skull base. Present study aimed to select the best discriminator from all mastoid parameters and to develop an equation for the determination of sex from Western Indian skulls via discriminant function analysis.

 Present study was carried out on total 160 human adult dry skull bones of known sex (90 male and 70 female) which were collected from the Anatomy Departments of various Medical and Dental Colleges across Gujarat, India. Three mastoid process parameters namely mastoid length, mastoid breadth, and antero-posterior diameters were measured on both the sides using a digital vernier calliper.

 All these mastoid variables are statistically highly significant (p <0.0001) for sexual dimorphism; each has a higher value in males than females. When the regression equation was applied, 96.2% of male skulls and 94.6% of female skulls were correctly classified.

 Mastoid length has the highest discriminative power among the three variables measured in this study. The knowledge of mastoid process measurements provided by the present study will be helpful in human osteology, anthropology, and forensic science for evaluation of sex from western Indian skulls.