RESUMO
Introduction: The sacral hiatus is located on the posterior aspect of the lower end of the sacrum, where theextradural space ends . The clinically significant features of the posterior surface of the sacrum are the triangularor inverted ‘U’ shape sacral hiatus and the sacral cornua.The knowledge of Anatomical variations of Sacralhiatus is significant while administration of Caudal Epidural Anaesthesia and it may help to improve its successrate.Aim: The purpose of this study is to recognize anatomical variations and additional landmarks of sacral hiatusin cases where the sacral cornua could not be identified and to assess proportions that may magnify the locationof the apex of the sacral hiatus and thus to find a practical solution for Caudal epidural block (CEB).Materials and methods: The present study was conducted on unknown sixty one complete and undamaged adult,dry sacral bones . The material was of undetermined age and gender. Anatomical measurements was carried outon these bones using a vernier calliper to the accurate of 0.1mm.Results: Variations in the shapes and their percentages of Sacral hiatus were observed namely Elongated, InvertedU, Irregular, Inverted V, Dumbbell and Bifid along with their distances and Angles of use in detecting the Apexwere measured. The location of Apex of Sacral hiatus was found at varying levels from upper end of S2 to lowerpart of S5 vertebrae. Also we measured the angles between the margins of the triangle formed by the twosuperolateral sacral crests and the sacral hiatus. Our measurements reveal this to be an equilateral triangle.Conclusion: This knowledge of variations in Human sacral hiatus provides a safe caudal epidural block beforesurgery and complications can be avoided.We believe that the equilateral character of the sacral triangleformed connecting the two posterior superior iliac spines and the apex of the sacral hiatus will be practicaladvantage to the clinician in ascertaining the location of the sacral hiatus during CEB.