Sacrum, Lateral View

Description

Curving inferiorly from L5, the male sacrum appears in lateral profile with its promontory positioned anterosuperiorly and its apex tapering posteroinferiorly toward the coccyx. The sacral ala flares superiorly, and the auricular surface sits on the lateral aspect, facing laterally to meet the ilium at the sacroiliac joint. Anterior to the median sacral crest, the fused sacral vertebral bodies create the concavity of the pelvic surface, while posterior elements form the dorsal contour seen in side view. Intervertebral discs between the lumbar vertebrae are included for orientation, ending at the L5 to S1 disc immediately superior to the sacral base. Lateral sacral anatomy is the reference frame for sagittal alignment, because the sacral slope and lumbosacral angle influence lumbar lordosis and load transfer into the pelvis. That relationship becomes concrete in spondylolisthesis at L5 to S1, where the sacral promontory and superior endplate orientation affect slip mechanics and surgical planning for reduction and fusion. The auricular surface is a practical landmark too, since sacroiliitis and degenerative sacroiliac joint disease concentrate pain around this articulation and its adjacent ligamentous attachments. Faculty can drop this plate directly into gross anatomy teaching on the pelvis and vertebral column, or into biomechanics lectures on spinopelvic parameters and posture. It also suits orthopedic and neurosurgical publishing when illustrating lumbosacral junction pathology, sacroiliac joint localization, or preoperative planning for lumbosacral instrumentation. Anatomical accuracy verified by SciePro's Medical Advisory Board.