ClinIQ Lexicon · Abbreviation

LES Lower Esophageal Sphincter

What LES means

The LES is the specialized segment of circular smooth muscle at the gastroesophageal junction that maintains tonic contraction at rest and relaxes with swallowing. Its resting tone forms the principal anti-reflux barrier against gastric contents entering the esophagus.

LES in clinical practice

Things that relax LES tone — fatty meals, caffeine, alcohol, nicotine, certain medications, and pregnancy — appear constantly as risk factors in GERD question stems. The ClinIQ GERD article explains how LES dysfunction translates into reflux physiology and therapy targets.

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