A Lateral View Of The Posterior Superior Iliac Spine's Structure

Description

Prominent in lateral profile, the posterior superior iliac spine (PSIS) projects from the posterior end of the iliac crest at the junction where the crest turns inferiorly toward the posterior border of the ilium. The sequence tracks the bony contour as the camera settles on the PSIS relative to the adjacent posterior iliac crest and the smoother, more anterior iliac fossa surface wrapping away from view. Subtle rotational motion clarifies how the PSIS sits posterior to the anterior superior iliac spine (ASIS) and superior to the posterior inferior iliac spine (PIIS), establishing a dependable orientation point on the pelvis. Clean cortical relief. Clinically, the PSIS is a palpation landmark for surface anatomy and procedural planning, commonly identified as the pair of dimples overlying the posterior pelvis and used to estimate the level of S2 in relation to the sacrum. That matters when teaching sacroiliac joint pain referral patterns, guiding SI joint injections, or discussing posterior pelvic fixation, where millimeters of bony trajectory determine whether hardware stays in the ilium or violates the greater sciatic notch region. Animation makes the depth cues honest, showing why a structure that feels superficial on the skin is still part of a complex three-dimensional iliac crest rim. Use it in gross anatomy labs to anchor pelvic orientation terminology (anterior versus posterior, superior versus inferior) before students tackle sacroiliac ligaments and gluteal compartment dissection, and in orthopedic or pain-medicine slide decks to illustrate palpation-based landmarking for SI joint assessment. It also fits medical publishing sidebars on low back pain examination, where a short moving view helps readers reconcile surface dimples with the underlying ilium. Anatomical accuracy verified by SciePro's Medical Advisory Board.