Motor disorder in pharyngoesophageal pouch.

Patients with a pharyngoesophageal pouch studied by esophageal manometry were shown to have premature relaxation of the upper esophageal sphincter. Postrelaxation contraction of the sphincter was therefore already in progress while pharyngeal contraction was taking place. This motor disturbance creates a physiological obstruction at the upper esophageal sphincter so that high pressures are built up in the pharynx. These conditions are conductive to herniation of the pharyngeal mucosa through any weak area in the muscle wall of the pharynx.