The Anatomical Structure And Location Of Ala Of The Sacrum

Description

Arising from the lateral aspect of the first sacral vertebra (S1), the sacral ala forms a broad, triangular wing that flares laterally and slightly anteriorly from the sacral promontory. As the animation orients the pelvis in anatomical position, the ala is seen continuous medially with the sacral body and superiorly with the lumbosacral junction at L5 to S1. Lateral to the ala, the auricular surface for the sacroiliac joint comes into view, while the anterior sacral foramina sit inferior and medial on the pelvic surface. Bony contours are rotated sequentially so the viewer can appreciate how the ala contributes to the superior pelvic brim. Orientation of the sacral ala matters in both biomechanics and procedure planning because it is the osseous corridor for sacral-alar and sacral-alar-iliac fixation trajectories, and its morphology influences safe screw angulation relative to the sacral foramina and lumbosacral trunk. Fracture patterns also track through this region, including Denis zone injuries near the foramina and lateral compression mechanisms that transmit force across the sacroiliac complex. Motion clarifies relationships that are easy to misread in static plates, separating the pelvic surface of S1 from the lateral articular region that interfaces with the ilium. Use this animation in gross anatomy and musculoskeletal anatomy teaching to anchor the sacrum within the axial skeleton and to introduce the pelvic inlet, sacroiliac joint anatomy, and common lumbopelvic instrumentation landmarks. It also fits spine and trauma education modules, surgical atlas supplements, and radiology correlation for CT evaluation of sacral fractures and preoperative planning of sacral-alar-iliac screws. Anatomical accuracy verified by SciePro's Medical Advisory Board.