Morphometric Analysis of Sexual Dimorphism in Foramen Magnum

Abstract

Introduction: The establishment of human sex identity is of paramount importance in the field of forensic
medicine especially when it comes to medico legal cases of disputed sex, completely decomposed or charred
bodies, and decapitated cadaveric remains, exhumation of skeletonized remains where skull is recovered
and referred to a forensic expert for opinion by the police, etc.
Methodology: Study sample includes 77 dry human skull bones obtained from department of forensic
medicine, department of anatomy and student volunteers of T.O.M.C.H & R.C. T. The sex of the skull
bone is estimated by using morphological characteristics. The anterio-posterior diameter and the transverse
diameter of the foramen magnum is measured using a Vernier caliper. The results are tabulated in Microsoft
Excel 2013 document and the areas of foramen magnum were calculated using the formulae derived by
Routal and Teixeira. Statistical analysis for correlation between the measurements and the sex of the skull
was performed using SPSS software.
Results: Majority of skulls belonged to the female sex with maximum distribution in 25 to 35 age group
followed by 18 to 25 age group. The length, breadth, and the area of foramen magnum are found to be larger
in males than females. However, statistically significant sex differences were observed only for the breadth
and areas of the foramen magnum.
Discussion: Our findings with regard to the sexing potential of foramen magnum dimensions found a
statistically significant difference for breadth of the foramen magnum but the sexual dimorphism index and
logistic regression for the same does not indicate a significant difference. The present research also reports
a statistically significant sex differences in the area of foramen magnum as derived by formula given by
Teixeira and Radinsky which is similar to that reported in earlier studies.
Conclusion: Parameters analyzed for sexual dimorphism of foramen magnum the area of the foramen
magnum proves to be a better predictor of sex compared to other features but foramen magnum alone should
not be considered for sexual differentiation unless the skull is mutilated.