Background: The sacrum, an enormous triangular bone, is formed when the five sacral vertebrae fuse together. While the dorsal wall of the sacral canal is generated by the fusing of the laminae, spines, and ossified ligamentum flava, the ventral wall is created by the fusion of the sacral vertebra's body. Numerous variations can be found in the sacral canal's dorsal wall. It might be entirely open all the way down. By injecting medications into the spinal canal, caudal epidural anaesthesia provides both analgesia and anaesthesia. One of the contraindications of caudal epidural block is the full agenesis of the sacral dorsal wall.