Anatomical Characteristics Of The Lateral Part Of The Sacrum

Description

Sacral ala and the adjacent lateral mass dominate the lateral aspect of the sacrum, flaring laterally from the fused transverse processes of the upper sacral vertebrae. Along this outer margin, the auricular surface sits superolateral to the pelvic sacral foramina and faces the ilium to form the sacroiliac joint, while the roughened sacral tuberosity lies immediately posterior to it for attachment of the interosseous sacroiliac ligaments. Inferiorly, the lateral border tapers toward the inferior lateral angle of the sacrum and approaches the coccygeal articulation at the apex. Thick bone. Understanding the lateral sacrum matters because it is both a load-transfer column from the vertebral column into the pelvic ring and a common site of clinically relevant injury and pain generation. Sacral ala fractures occur in osteoporotic insufficiency patterns and after pelvic ring trauma, and the relationship between the ala, auricular surface, and neural foramina determines safe corridors for iliosacral screw fixation and for sacroiliac joint injections. The fixed perspective emphasizes surface texture differences, smooth articular cartilage-bearing auricular surface versus the ligamentous tuberosity, which is where anatomy exams and operative planning often focus. Orthopaedic trauma and spine surgery texts can pair this illustration with pelvic inlet or outlet radiographs to explain why trans-sacral and iliosacral hardware must respect the foraminal boundaries. In gross anatomy, physical therapy, or chiropractic curricula, the image supports teaching of sacroiliac joint anatomy, palpation landmarks near the posterior superior iliac spine, and mechanisms of SI joint–mediated low back pain. Anatomical accuracy verified by SciePro's Medical Advisory Board.