The sacrospinous ligament converts the greater sciatic notch into the greater sciatic foramen. Which structure exits the greater sciatic foramen BELOW the piriformis muscle?

• A Superior gluteal nerve and vessels
• B Sciatic nerve only
• C Piriformis, sciatic nerve, and superior gluteal nerve
• D Pudendal nerve, internal pudendal vessels, nerve to obturator internus, inferior gluteal nerve ✓

Explanation

The piriformis muscle itself exits the greater sciatic foramen and divides it into two compartments. Above piriformis: the superior gluteal nerve and vessels. Below piriformis: the sciatic nerve, inferior gluteal nerve and vessels, pudendal nerve (which then re-enters the pelvis through the lesser sciatic foramen), internal pudendal vessels, posterior cutaneous nerve of the thigh, nerve to obturator internus, and nerve to quadratus femoris. The superior gluteal nerve exits above piriformis. Knowledge of this arrangement is essential for interpreting piriformis syndrome and safe gluteal injection sites.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.