Dimensions of Foramen Magnum for Estimation of Sex in Nepalese Population

Abstract

Human skull is considered as one of the most reliable bones for sex differentiation. This study is an attempt to estimate sex, using variations in dimensions of Foramen Magnum among the Nepalese population. Most studies on the skull have been carried out in dry skull, using ectocranial measurements. This study on sexual dimorphism in Foramen Magnum of Nepalese population was carried out in wet skull and measurements are taken intracranially by using sliding Vernier’s caliper. A cross-sectional study of 96 medico-legal autopsies (53 males and 43 females) was conducted at Department of Forensic Medicine, Institute of Medicine, Kathmandu, to establish reference standards for sexual dimorphism of dimensions of Foramen Magnum. The mean antero-posterior diameter (APD) was found to be 33.45 mm in males and 30.70 mm in females. The mean transverse diameter (TD) was found to be 27.64 mm in males and 25.19 mm in females. Both APD and TD were found to have statistically significant dimorphism between the sexes. Discriminant function analysis showed that the accuracy ranged between 55.8% and 81.4 % with use of both APD and TD showing the most accurate classification. Binary logistic regression showed that 69.8% were correctly classified as female and 79.2 % were correctly classified as male and 75% on overall population.