Pyloric sphincter
Musculus sphincter pyloricus
DigestiveOrgansAbdomen
- What it is
- Thick ring of circular smooth muscle at the outlet of the stomach, felt as a firm ridge between the antrum and the duodenum.
- Function
- Meters chyme into the duodenum a few millilitres at a time and limits reflux of bile back into the stomach.
- Size
- Ring about 2-3 cm across; the muscle is about 0.5 cm thick.
- Clinical note
- In infantile hypertrophic pyloric stenosis the muscle thickens, causing projectile vomiting at 2-8 weeks of age; it is cured by splitting the muscle (pyloromyotomy).