Nerve
Pudendal nerve
Main nerve of the perineum
High-yield
S2, S3, S4 keep the pelvic floor off the floor. Blocked at the ischial spine for obstetric analgesia.
Overview
The chief nerve of the perineum, supplying the external genitalia, perineal muscles, and the external anal and urethral sphincters.
Reference facts
- Roots
- S2, S3, S4 (sacral plexus)
- Course
- Exits the greater sciatic foramen below piriformis, hooks around the ischial spine, re-enters through the lesser sciatic foramen, and runs in the pudendal (Alcock's) canal
- Motor
- External anal sphincter, external urethral sphincter, and perineal muscles
- Sensory
- Perineum and external genitalia
Frequently asked questions
What are the roots of the pudendal nerve?
The pudendal nerve arises from S2, S3, S4 (sacral plexus).
What muscles does the pudendal nerve supply?
The pudendal nerve supplies the external anal sphincter, external urethral sphincter, and perineal muscles.
What is the sensory distribution of the pudendal nerve?
The pudendal nerve carries sensation from the perineum and external genitalia.
What is the course of the pudendal nerve?
Exits the greater sciatic foramen below piriformis, hooks around the ischial spine, re-enters through the lesser sciatic foramen, and runs in the pudendal (Alcock's) canal.