Sacral Tuberosity, Lateral View

Description

Sacral tuberosity dominates the posterior part of the lateral sacrum, positioned immediately posterior to the auricular surface that articulates with the ilium at the sacroiliac joint. The pitted, roughened area lies dorsal to the smooth, ear-shaped articular facet and blends medially with the intermediate and lateral sacral crests formed by fused posterior elements. Superiorly, the tuberosity approaches the sacral ala near the level of S1, while inferiorly it tapers toward the posterolateral margin of the lower sacral segments. Surface texture is the story here. Clinically, the sacral tuberosity matters because it anchors the interosseous sacroiliac ligament and portions of the posterior sacroiliac ligament, structures that transfer load between spine and pelvis and often generate pain patterns attributed to sacroiliac dysfunction. A fixed lateral perspective helps distinguish the nonarticular ligamentous attachment zone from the adjacent auricular surface, an anatomic distinction that becomes relevant when correlating CT or radiographic sclerosis, erosions, or ankylosis in spondyloarthropathies to the correct surface. Orthopaedic planning also benefits, since the relationship of this roughened posterior area to the sacroiliac joint line frames safe corridors and reduction goals in pelvic ring injuries, including iliosacral screw fixation and sacral fracture classification. Gross anatomy and osteology teaching sessions can use this illustration to reinforce side determination of an isolated sacrum and to test identification of sacroiliac joint landmarks without the distraction of the entire pelvic ring. It also suits figures in orthopaedic trauma, spine, and rheumatology publications discussing sacroiliac joint stability, posterior ligament anatomy, and sites of enthesopathy. Anatomical accuracy verified by SciePro's Medical Advisory Board.