- Failure to relax; referring especially to visceral openings such as the pylorus, cardia, or any other sphincter muscles. [G. a- priv. + chalasis, a slackening]- cricopharyngeal a. functional obstruction at the level of the upper esophageal sphincter due to failure of relaxation of the cricopharyngeal muscles; often associated with a pharyngoesophageal diverticulum. SYN: a. of the upper sphincter, hypertensive upper esophageal sphincter.- esophageal a. failure of normal relaxation of the lower esophageal sphincter associated with uncoordinated contractions of the thoracic esophagus, resulting in functional obstruction and difficulty swallowing. SYN: a. of the cardia, cardiospasm.
* * *acha·la·sia .ā-kə-'lā-zh(ē-)ə n failure of a ring of muscle (as a sphincter) to relax <\achalasia of the esophagus> <\achalasia of the anal sphincter> compare CARDIOSPASM
* * *n.a condition in which the normal muscular activity of the oesophagus (gullet) is disturbed, especially failure of an abnormally strong sphincter at the lower end, which delays the passage of swallowed material. It may occur at any age: symptoms include difficulty in swallowing liquids and solids, slowly increasing over years; sometimes regurgitation of undigested food; and occasionally severe chest pain caused by spasm of the oesophagus. Diagnosis is by a barium X-ray examination and sometimes manometric studies (see manometry). Treatment is by forceful stretching of the tight lower end of the oesophagus (cardia), by surgical splitting of the muscular ring in that area (cardiomyotomy or Heller's operation), or by injecting botulinum toxin into the sphincter.
* * *ach·a·la·sia (ak″ə-laґzhə) [a-1 + chalasia] failure of the smooth muscle fibers of the gastrointestinal tract to relax at a point of junction of one part with another; usually used to denote esophageal achalasia.
Medical dictionary. 2011.