Diseases of the esophagus.

Achalasia cardia

incomplete relaxation of the lower esophageal sphincter in response to swallowing. This produces functional obstruction of the esophagus, with consequent dilation of the more proximal esophagus

Manometric studies show three major abnormalities in achalasia:

(1) aperistalsis, (2) partial or incomplete relaxation of the lower esophageal sphincter with swallowing, and (3) increased resting tone of the lower esophageal sphincter

Defect of intrinsic inhibitory innervation of the lower esophageal sphincter and smooth muscle segment of the esophageal body.