The pudendal nerve (S2, S3, S4) exits the pelvis through which foramen, winds around which structure, and re-enters the perineum through which canal?

• A Obturator foramen; obturator internus; obturator canal
• B Greater sciatic foramen; ischial spine; lesser sciatic foramen into Alcock's (pudendal) canal ✓
• C Lesser sciatic foramen; sacrospinous ligament; greater sciatic foramen
• D Greater sciatic foramen; sacrotuberous ligament; obturator foramen

Explanation

The pudendal nerve exits the pelvis through the greater sciatic foramen (below piriformis), winds around the ischial spine and sacrospinous ligament, and re-enters the perineum through the lesser sciatic foramen into the pudendal (Alcock's) canal on the medial surface of the ischiorectal fossa. This route is the basis for pudendal nerve block — the needle passes transvaginally to the ischial spine. Pudendal nerve injury during childbirth or cycling causes perineal numbness and sphincter dysfunction.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.