Sexual Dimorphism and Regional Difference in Size of Sacrum: A Study in Eastern India

Objective: To study the sexual dimorphism and regional differences of the varied features of the sacrum in eastern India and record the significant anthropometric indices of the study. Background: In the determination of personal individuality from adult human skeletal remains, the pelvis affords the best marked and reliable characteristics for distinguishing sex in 90-95% subjects. Since the sacrum is an integral element of the axial skeleton and contributes to the functional differences of the pelvic girdle between the two genders, it has a distinct medico-legal importance in ascertaining the sex by means of the anthropometric measurements observed upon it. Materials and Methods: 250 normal human adult sacra were acquired from the Departments of Anatomy and Anthropology under the different medical & science colleges in Kolkata, West Bengal, during the years 2004-2009 for the study of anthropometric measurements and sexual dimorphism. The measurements included length, width, curved length of the sacra, antero-posterior and transverse diameter of the first sacral vertebrae, sacral index, corporo-basal index etc. Demarking points [DP] for these parameters were used for identification of the sex of the sacrum. Results: The results of the present study were compared with previous studies for regional differences. The sacral index (44.7%) was found to be the most useful criterion metric data for identification of the female sacrum followed by curvature index (26.8%) while in case of the male sacrum, corporo-basal index (23.6%) was found to be most useful, followed by sacral index (9.4%) in this study. Summary and Conclusion: To study sexual dimorphism in human sacrum, 127 male and 123 female sacra were studied from Kolkata District, West Bengal. This study may have importance in Anatomy, Anthropology and Forensic Medicine.