The Anatomical Characteristics Of The Base Of The Sacrum

Description

Framed in anatomical position, the animation focuses on the basis ossis sacri formed by the first sacral vertebra (S1), with the promontorium projecting anteriorly and superiorly at the lumbosacral junction. As the sequence rotates the specimen, the superior articular processes of S1 are seen posterolaterally flanking the entrance to the canalis sacralis, while the alae sacralis broaden laterally toward the iliac articulations. The lumbosacral facets and margins of the vertebral body come into view in alternation, clarifying how the base transitions from an anterior pelvic surface to a posterior sacral surface. Clinically, the sacral promontory is a hard landmark for pelvic inlet assessment and for staging cephalopelvic disproportion, and it defines the anterior boundary of the lumbosacral angle where shear forces concentrate in spondylolisthesis at L5 to S1. Orientation matters. The animated turn-around makes it easier to distinguish the promontory from adjacent S1 endplate contours and to appreciate how the superior articular facets guide motion and load transfer across the lumbosacral joint, details that are often flattened in static diagrams. Use this asset for gross anatomy teaching on the bony pelvis and vertebral column, for obstetrics and gynecology modules on pelvic inlet landmarks, and for spine texts discussing lumbosacral biomechanics and preoperative planning for L5 to S1 fusion trajectories. It also fits radiology education when correlating the promontory and S1 endplate with sagittal CT or MR reconstructions used in spinopelvic parameter measurement. Anatomical accuracy verified by SciePro's Medical Advisory Board.