Pelvic Bones Without the Sacrum, Posterior View

Description

Centered on the paired os coxae of an adult male, the posterior aspect of the ilium, ischium, and pubis is presented with the sacrum removed, leaving the auricular surfaces and posterior sacroiliac region as open medial margins. Superiorly, the iliac crests curve laterally into the posterior superior iliac spines, while the posterior inferior iliac spines sit immediately inferior and medial to the greater sciatic notches. Laterally, each acetabulum faces posterolaterally relative to the pelvic cavity, and inferiorly the ischial bodies and ischial tuberosities bracket the obturator foramina, with the pubic rami contributing anteromedially toward the (partly obscured) symphyseal region. Clear bony geometry. No axial element. Removing the sacrum makes the posterior pelvic ring easier to teach because you can isolate the hip bones and their ligament attachment sites without the visual interference of the median sacral crest or sacral foramina. This perspective helps orient clinicians to landmarks used in posterior pelvic trauma assessment, where posterior ring instability often tracks through the sacroiliac complex, and it also clarifies the relationship of the greater sciatic notch to the expected course of the sciatic nerve after it exits the pelvis via the greater sciatic foramen. The male morphology, with a narrower subpubic angle and a more robust iliac architecture, reads well from behind. Use it in gross anatomy and osteology labs to cue students on posterior iliac spine palpation, acetabular orientation, and the bony boundaries relevant to posterior hip approaches. It also fits orthopedic and trauma publications discussing pelvic ring fracture patterns, sacroiliac fixation trajectories, or landmark-based injection and palpation guides. Anatomical accuracy verified by SciePro's Medical Advisory Board.