Chalasia of the upper esophageal sphincter.

Four patients with absence of stable tonus (chalasia) of the pharyngo-esophageal segment, i.e., the cricopharyngeal muscle and the adjacent cervical esophagus, are reported. The tonus between swallows was completely absent in 2 patients and was seriously impaired in 2. All patients had normal peristalsis in the cricopharyngeal muscle but delayed or absent peristalsis in the cervical esophagus. In one patient the relaxation of the cricopharyngeal muscle during the passage of the bolus was incomplete. Various other functional abnormalities in the pharynx were present as well. The observed abnormalities are interpreted in relation to current understanding of motor mechanisms in the area of the pharyngo-esophageal segment.