Lower esophageal sphincter

Lower Esophageal Sphincter

The Lower Esophageal Sphincter (LES) is a bundle of muscles at the low end of the esophagus, where it meets the stomach. When the LES is closed, it prevents acid and stomach contents from traveling backwards from the stomach. The LES muscles are not under voluntary control.

Function

The primary function of the LES is to prevent gastroesophageal reflux (GER). It does this by closing the pathway back into the esophagus after food has passed into the stomach.

Clinical significance

If the LES is weak or relaxes inappropriately, stomach acid can flow back up into the esophagus, causing heartburn and potentially damaging the esophageal lining. This condition is known as gastroesophageal reflux disease (GERD).

Diagnosis

Diagnosis of LES dysfunction is complex and usually requires endoscopy, manometry, and pH monitoring.

Treatment

Treatment for LES dysfunction typically involves lifestyle changes and medications. Surgery may be considered in severe cases.

See also

• Esophagus
• Gastroesophageal reflux disease
• Heartburn

Lower esophageal sphincter Resources
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