Sacrum, Anterior View

Description

Rising from the lumbosacral junction, the lumbar vertebral bodies and intervertebral discs lead inferiorly into the anterior (pelvic) surface of the male sacrum, rendered in contrasting color to separate it from the lumbar spine. Four pairs of anterior sacral foramina punctuate the sacral ala and bodies bilaterally, aligned in vertical columns lateral to the fused transverse ridges that mark the former intervertebral disc planes. The sacral promontory forms the superior anterior margin, projecting anteriorly and superiorly at the S1 body, while the broad base narrows inferiorly toward the apex that will articulate with the coccyx. Clear midline symmetry. Clinically, an anterior view emphasizes the relationship between the lumbosacral disc (L5 to S1), the sacral promontory, and the pelvic inlet, a set of landmarks used when discussing spondylolisthesis at L5, lumbosacral transitional anatomy, and pelvic incidence. The anterior sacral foramina matter because they transmit the ventral rami of S1 to S4 and accompanying vessels, structures at risk during anterior approaches to the lumbosacral spine and pelvic surgery, and relevant when correlating sacral nerve symptoms with foraminal stenosis or fracture lines. Color separation also supports teaching the concept of sacral fusion and the segmental origin of the sacral plexus. Use this plate in anatomy and radiology teaching to orient learners to the pelvic surface of the sacrum before moving to CT or MRI, where the anterior foramina and the S1 promontory are common reference points. It also fits well in orthopedic and neurosurgical materials covering anterior lumbar interbody fusion (ALIF) at L5 to S1 and in obstetrics and gynecology content explaining pelvic inlet geometry. Anatomical accuracy verified by SciePro's Medical Advisory Board.