MATERIAL and METHODS: The study included 50 dry human sacra, of unspecified sex, in the Department of Anatomy at a medical college in South India. The sex was determined using the sacral, auricular and curvature index. The variations and morphometry of the sacra were documented and tabulated.

RESULTS: It was observed that the inverted U shape of sacral hiatus was common in both males (n=24) and females (n=26). There was one female sacrum with complete dorsal wall agenesis. In males, the length of the apex of sacral hiatus from 1st sacral spine was 5.82 cm ± 1.27 and in females, it was 6.02 cm ± 1.08. Sacral hiatus depth in males was 0.56 cm ± 0.16 and in females 0.54 cm ± 0.14. The width of sacral hiatus at the cornua in males was 1.42 cm ± 0.29 and in females, it was 1.46 cm ± 0.38

CONCLUSION: Knowledge of incidences of variations in the morphology and morphometry of the sacral hiatus across various population groups is paramount for the success and reliability of epidural anesthesia. The success rate of such procedures depends on the clinicians? understanding of the discrepancy in the sacral hiatus. Keywords : Caudal epidural anesthesia, Sacral canal, Sacral hiatus, Spina bifida, Back pain