Detailed Illustration of the Female Sacral Region

Description

Centered in the posterior pelvis, the sacrum sits inferior to L5 and superior to the coccyx, its broad base continuous with the alae that articulate laterally with the iliac bones at the sacroiliac joints. Median, intermediate, and lateral sacral crests trace the fused spinous and transverse processes, while paired dorsal sacral foramina open on either side of the midline for the posterior rami of the sacral spinal nerves. Superiorly, the sacral promontory and anterior margin of S1 define the pelvic inlet, and the auricular surfaces lie posterolateral, just medial to the posterior superior iliac spines. Female sacral morphology matters because pelvic dimensions and obstetric mechanics depend on the relationship between the sacral promontory, sacral curvature, and the interspinous and intertuberous distances of the bony pelvis. A short, broad sacrum with less pronounced curvature increases the anteroposterior diameter of the pelvic outlet, while a prominent promontory reduces the obstetric conjugate and can contribute to cephalopelvic disproportion. Pain localizing to the posterior superior iliac spine region often implicates the sacroiliac joint, and this posterior bony map supports image-guided approaches to SI joint injection, evaluation of sacral insufficiency fractures, and interpretation of sacral nerve root foraminal encroachment. Use this artwork for pelvic anatomy and obstetrics teaching, radiology correlations (plain film, CT, MRI) of the sacrum and SI joints, and clinical manuals covering posterior pelvic pain, caudal epidural access landmarks, and sacral fracture classification. A clean reference. Anatomical accuracy verified by SciePro's Medical Advisory Board.