Upper esophageal sphincter: pre and post-laryngectomy--a normative study.

Correlation of anatomical, surgical, manometric, and radiographic observations leads to the conclusion that the normal high pressure zone of the pharyngoesophageal junction is composed of two parts: an annular muscular sphincter in the most proximal part of the upper esophagus and, above this, a complex pinchcock sphincter composed of the cricoid cartilage anteriorly and cricopharyngeus muscle laterally and posteriorly. The pinchcock part of the sphincter produces a high pressure zone in a predominantly anteroposterior direction. After laryngectomy, the sphincter becomes completely annular and behaves like a pure musculare constrictor; it is likely that both the cricopharyngeus and the upper esophageal circular muscles constitute the postlaryngectomy pharyngoesophageal high pressure zone. The relative contributions of the pinchcock segment (upper part) and annular constrictor segment (lower part) to the overall function of the upper esophageal sphincter have yet to be established in man.