Sexual dimorphism in sacrum

Abstract

The sacrum is a large triangular fusion of five vertebrae and forms the posterior wall of the pelvic cavity. It supports the spine and  provides stability to the pelvis to transmit body weight. Determination of sex from the skeletal remains is of tremendous medico-legal  importance for establishing the identity of an individual. Sacrum has always attracted the attention of medico-legal experts for  establishing sex, possibly because of its contribution to pelvic girdle and associated functional sex differences. Hence, it becomes  necessary to study the various parameters of sacrum to identify a male from a female sacrum. The aim of the present study was to  investigate the sex differences in an adult human sacrum and thus identify a male from a female sacrum using various parameters. 254  dried, completely ossified, grossly normal human adult sacrum of both sexes was taken from Department of Forensic Medicine and  Department of Anatomy of Mysore Medical College & Research Institute, Mysuru and from students of 1st year MBBS. In our study,  the male sacrum shows significantly higher values for ventral straight length, ventral curved length, transverse diameter of S1 and  anteroposterior of S1, than the female sacrum, while the female sacral index showed higher values when compared with that of male.  Demarking point of the sacrum helps in differentiating the two sexes. The most useful index for sex determination of sacrum in the  present study is sacral index. Continued study over a period of time in a defined area will definitely help in establishing the  anthropometric standards.