A neurosurgeon approaches the sacrospinous ligament during a perineal procedure. The target nerve leaves the pelvis through the greater sciatic foramen below piriformis, hooks around the sacrospinous ligament, and re-enters the pelvis through the lesser sciatic foramen. Which nerve follows this course?

• A Superior gluteal nerve
• B Nerve to obturator internus
• C Pudendal nerve ✓
• D Posterior femoral cutaneous nerve

Explanation

The pudendal nerve (S2-S4) uniquely exits through the greater sciatic foramen below piriformis, winds around the sacrospinous ligament, and re-enters the pelvis through the lesser sciatic foramen to run in Alcock's (pudendal) canal on the lateral wall of the ischiorectal fossa. The nerve to obturator internus also passes below piriformis but continues out of the pelvis without re-entering it.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.