An Anatomical Study of Variations of Sacral Hiatus in Sacra of North Indian Origin and Its Clinical Significance

Sacrum is formed by the fusion of five sacral vertebrae and forms the lower part of vertebral column. The opening present at the lower end of sacral canal is known as sacral hiatus. Anatomical variations in morphology and morphometry of sacral hiatus are important clinically as well as surgically. 159 dry clean human Sacra were taken from Department of Anatomy, Sri Guru Ram Das Institute of Medical Sciences and Research Vallah (Amritsar). Various shapes of sacral hiatus were observed which included inverted U (42.95%), inverted V (27.51%), irregular (16.10%), dumbbell (11.40%) and bifid (2.01%). The apex of sacral hiatus was commonly found at the level of 4th sacral vertebra in 56.36%. The mean length of sacral hiatus was 22.69 mm. The mean anteroposterior diameter of sacral canal at the apex of sacral hiatus was 6.49 mm. Narrowing of sacral canal at the apex of sacral hiatus (diameter less than 3 mm) was observed to be high (5.36%). The knowledge of anatomical variations of dimensions of sacral hiatus is important while doing caudal epidural block and it may help to improve its success rate.