cricopharyngeal incoordination, a defect in the normal swallowing reflex. The cricopharyngeus muscle ordinarily serves as a sphincter to keep the top of the esophagus closed except when the person is swallowing, vomiting, or belching. The trachea remains open for breathing, but air normally does not enter the esophagus during respiration. In swallowing the reverse effect occurs, and the larynx is closed while food slides past it into the esophagus, which is located immediately behind the larynx. When the somewhat complex series of neuromuscular actions is not properly coordinated as a result of disease or injury, the patient may choke, swallow air, regurgitate fluid into the nose, or experience discomfort in swallowing food. See also dysphagia.
