External anal sphincter
Hips & glutes
- Origin
- Anococcygeal ligament (from the tip of the coccyx)
- Insertion
- Perineal body
- Action
- Keeps the anus closed under voluntary control
- Nerve supply
- Inferior anal nerve (pudendal nerve, S2–S4) and perineal branch of the fourth sacral nerve (S4)
A ring of muscle around the anal canal that is under voluntary control. It keeps the anus closed and relaxes during bowel movements.
External anal sphincter anatomy page →