Achalasia

Achalasia or acalasia is a failure of a ring of muscle (as a sphincter) to relax (completely). It refers most commonly to esophageal achalasia, which is a neuromuscular disorder of the esophagus characterized by (1) the reduced ability to move food down the esophagus (peristalsis), and (2) the inability of the cardia (also called lower esophageal sphincter or "LES")- to relax properly in response to swallowing. Synonyms are achalasia cardiae, cardiospasm, dyssynergia esophagus, esophageal a ...