Determination of Sexual Dimorphism from Foramen Magnum in an Eastern Indian Population

Abstract

Human identification is an important arena of forensic investigation, it includes sex determination which becomes extremely difficult in  fragmented skeletal remains. Skull dimensions are measured for the purpose of sexual dimorphism which vary in different populations. In  this study, we attempted to analyse the measurements from adult human skulls and employ discriminant function to predict sex accurately.  A manual vernier calliper was used to measure the antero-posterior (AP) diameter and transverse diameter of foramen magnum of 88  skulls (49 males, 39 females) from the collection housed at the department of Anatomy, RG KAR medical college and Calcutta medical  college. The Wilk's lambda for the model is 0.795. The discriminant function equation is, Df= 3.342× (APdiameter of foramen magnum)  +0.725× (Transverse diameter of foramen magnum) -13.641(constant). The cut-off point is 0.505. So above this value 0.505, the cases are  male and below it, the cases are female. On comparing the measurements, we found that antero-posterior dimensions and transverse  dimensions of foramen magnum were greater in males than females. Collectively, all the results indicate that dimensions of foramen  magnum can be used as a moderate indicator for sex determination in regional populations.