Morphometric Analysis of Human Foramen Magnum and occipital condyles for Sex Determination in Dry Adult Skulls of Belgaum District- A Cross Sectional Study

Abstract

Background and Objectives: Anthropological study of bones play an important role in determining the sex, age and stature of an individual. Cranium is one of the good indicators for sexual dimorphism by morphometric and morphological analysis. The basi-cranium is protected by a large soft tissue mass comprising of muscles, tendons and ligaments. So in case of fragmentary human remains where no other skeletal remains are preserved the intact occipital region may prove useful for determining the gender. Hence this study was conducted to analyze morphometrically the foramen magnum and occipital condyles for sex determination in dry adult skulls of Belgaum district. Methods: This study was conducted on 100 foramina magna and 200 occipital condyles of 100 dry adult human skulls (50 male & 50 female) in the Department of Anatomy, J. N. Medical College, Belgaum. Morphological variants in the shape of foramen magnum and occipital condyles were noted. The antero-posterior diameter, transverse diameter and the indices of foramen magnum and occipital condyles (right and left) were measured using standard techniques. Students ‘t’ test was employed for statistical analysis. Results: It was observed that 36% of foramina magna were oval shaped, 20% were tetragonal, 19% were egg shaped, 14% were hexagonal, 9% were pentagonal and 2% were round shaped. The incidence of oval and hexagonal shaped foramen magnum was higher in male skulls and that of egg-shaped, pentagonal & round foramen magnum was higher in female skulls. The antero-posterior diameter of foramen magnum of male skulls was higher than the female skulls. No significant difference in the transverse diameter of foramen magnum of male and skulls was found. The foramen magnum index of male skulls was higher than the female skulls. 26% of right occipital condyles were oval shaped, 22% were S-shaped, 14% were triangular, 13% were kidney-shaped, 12% eight-shaped, 7% quadrangular, 2% round, 2% two-portioned and 2% were deformed. 23% of left occipital condyle were oval, 18% triangular, 18% eight-shaped, 18% S-shaped, 8% kidney shaped, 8% quadrangular, 3% deformed, 2% round and 2% were two-portioned. The antero-posterior diameter of occipital condyles (right and left) in male skulls was higher than the female skulls. There was no significant difference in the transverse diameter of occipital condyles (right and left) in male and female skulls. The occipital condyle index (right and left side) in male skulls was higher than the female skulls. Interpretation and Conclusion: The results of this study with respect to the morphometric analysis of foramen magnum and occipital condyle are in correlation with the results of various studies mentioned in the literature. This study also provides additional information on different shapes and indices of foramen magnum and occipital condyles and its relation to sex determination which is useful for anthropologists, morphologists & forensic experts and the neurosurgeons in dealing with lesions of posterior cranial fossa.