Morphometric study of variations of sacral hiatus among West Bengal population and clinical implications

Abstract

The study was conducted on one hundred and seventeen human sacra to categorize the sacral hiatus of West Bengal population to improve the accuracy of caudal epidural block for anesthesia and analgesia. Various contours of hiatus were observed in this study which included inverted U (70.09%), inverted V (14.53%), irregular (12.82%), bifid (1.71%) and dumbbell (0.85%).The most frequently observed positions of apex and base of the hiatus were fourth and fifth sacral vertebrae respectively (74.36% and 95.73%). The average length, width and depth of hiatus were 20.21 mm, 12.10 mm and 6.02 mm with standard deviation of 7.7 3mm, 3.13 mm and 2.43 mm respectively. All the measurements were taken by Vernier calipers. Only in 27.35% cases the points on the lateral sacral crests at the level of first sacral foramina formed an equilateral triangle with the apex of the hiatus and thus could be used as an important landmark to locate sacral hiatus.