Ala Of The Sacrum, Superior View

Description

Sacral ala occupy the superolateral margins of the sacral base, flaring laterally from the body of S1 like broad wings on either side of the sacral promontory. From a superior perspective, the paired alae frame the entrance to the sacral canal posteriorly while running lateral to the superior articular processes of S1, which articulate with the inferior articular processes of L5 at the lumbosacral junction. Each ala blends laterally toward the auricular surface and sacroiliac region, with its cortical contours defining the transition from the axial spine to the pelvic ring. Bony landmarks read cleanly. Sacral ala matter whenever the load path from L5 to the ilia is discussed, because their trabecular architecture and broad surface area distribute compressive forces across the sacroiliac complex and the upper sacrum. Insufficiency fractures commonly involve the sacral ala and can produce the classic H-pattern on bone scintigraphy, while occult vertical fractures through the ala are a known pain generator after low-energy falls in osteoporotic patients. A fixed superior view supports correlation with axial CT and inlet-style pelvic orientation, helping you identify where the alar cortex lies relative to the sacral canal and the lateral recesses that are relevant to screw trajectory planning. Use this illustration in pelvis and spine anatomy curricula to teach the sacral base, ala, and their relationship to L5 and the sacroiliac joint, and in orthopedic trauma or radiology publications discussing pelvic ring injury patterns and sacral insufficiency fractures. It also suits operative education for iliosacral screw fixation and minimally invasive SI joint fusion, where appreciating the alar “wing” as a lateral corridor helps avoid canal breach. Anatomical accuracy verified by SciePro's Medical Advisory Board.