Nerve to the Obturator Internus and Superior Gemellus, Posterior View

Description

Arising from the anterior divisions of L5 to S2 within the sacral plexus, the nerve to the obturator internus courses posteriorly along the lateral pelvic wall before exiting the pelvis through the greater sciatic foramen, inferior to the piriformis. It then hooks around the ischial spine and sacrospinous ligament, re-entering via the lesser sciatic foramen to reach the obturator internus on its pelvic surface, while a branch supplies the superior gemellus on the posterior hip. Nearby, a posterior view would also logically place the sciatic nerve and posterior femoral cutaneous nerve deep to gluteal musculature, with the ischium, acetabulum, and proximal femur framing the course. Bilateral symmetry clarifies right left differences in branching. A tight corridor. This nerve matters because its path through the greater and lesser sciatic foramina makes it a reliable landmark in posterior hip anatomy and a potential victim in deep gluteal pain syndromes. During a posterior approach to the hip or exposure around the ischial spine, confusion with the nerve to quadratus femoris or inferior gluteal nerve can lead to selective denervation of the obturator internus and superior gemellus, weakening external rotation and altering dynamic stability of the femoral head. The relationship to the sacrospinous ligament also explains why pelvic procedures near the ischial spine, including pudendal nerve blocks or repairs for pelvic organ prolapse, demand careful spatial awareness. Educators will find this plate suited for gross anatomy labs covering the sacral plexus, gluteal region, and short external rotators, and for teaching the foraminal exits that students often mix up. It also fits operative anatomy chapters and surgical atlases describing posterior hip exposure, sciatic notch anatomy, and the internervous planes around piriformis and obturator internus. Anatomical accuracy verified by SciePro's Medical Advisory Board.