Morphology of Sacrum and its Variations

Abstract

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, Morphology and Morphometry of Sacral hiatus are important clinically as well as surgically 1 . This study was carried out on 75 dry human sacra of unknown sex to know different features of Sacrum, anatomical variations of sacrum and to study the variations of sacral hiatus. Anatomical variations – failure of formation of superior articular process and lamina of left first sacral vertebra, incomplete development and fusion of second sacral vertebra, multiple foramens on either side of spinous process above the sacral hiatus, multiple foramens in the dorsal surface of base of the sacrum behind the auricular surface, incomplete median crest, bilateral five pelvic and dorsal foramens were identified. Various shapes of sacral hiatus were observed which included inverted u, inverted v, irregular, dumbbell and bifid 2 . The apex of sacral hiatus was commonly found at the level of fourth sacral vertebra. The mean length of sacral hiatus was measured. The mean anteroposterior diameter of sacral canal and narrowing of sacral canal at the apex of sacral hiatus was measured 1&2 . The knowledge of anatomical variations of Sacrum and variations of Sacral hiatus are clinically important for Caudal epidural block in Pediatric, Obsteric, Orthopedic, Urologic and Surgical practice. The reliability and success of Caudal epidural block depends upon Knowledge of Variations of Sacrum and Variations of Sacral hiatus.