Sacral Tuberosity

Description

Sacral tuberosity occupies the rough, pitted area on the posteromedial aspect of the sacrum, immediately posterior to the ear-shaped auricular surface that articulates with the ilium at the sacroiliac joint. From this fixed posterior oblique presentation, the tuberosity sits lateral to the dorsal sacral foramina and inferolateral to the sacral ala, with its irregular texture contrasting against the smoother articular cartilage-bearing auricular region. The median sacral crest and adjacent intermediate and lateral sacral crests provide midline and paramedian reference points, while the tuberosity remains the key lateral landmark on the dorsal pelvic surface. Functionally, the sacral tuberosity anchors the strong posterior sacroiliac ligaments, including the interosseous and posterior sacroiliac ligament complexes, which span to the iliac tuberosity and stabilize the posterior pelvic ring. That ligamentous tethering explains why tenderness localizes near the posterior superior iliac spine in sacroiliac joint dysfunction and why inflammatory sacroiliitis (for example in ankylosing spondylitis) produces erosive change around the auricular surface while sparing, or secondarily involving, adjacent nonarticular bone. Small details matter here. The contrast between articular and nonarticular surfaces helps learners distinguish load-bearing joint topography from ligament attachment zones when interpreting pelvic CT, MRI, or surgical anatomy. Use this illustration in gross anatomy and orthopaedic teaching to orient the dorsal sacrum and to label the auricular surface, sacral tuberosity, dorsal sacral foramina, and crests without ambiguity. It also supports figure plates for spine and pelvis chapters discussing sacroiliac joint pain generators, posterior pelvic ring injury patterns, and safe corridors for sacroiliac screw fixation relative to the sacral ala. Anatomical accuracy verified by SciePro's Medical Advisory Board.