pharyngoesophageal

Pharyngoesophageal refers to the region where the pharynx transitions into the esophagus, particularly the pharyngoesophageal segment that includes the upper esophageal sphincter (UES). It is a functional zone critical for coordinating swallowing and protecting the airway.

Anatomy in this region centers on the upper esophageal sphincter, formed mainly by the cricopharyngeus muscle, with contributions from the thyropharyngeus part of the inferior constrictor. The pharyngoesophageal segment lies at the boundary between the hypopharynx and the cervical esophagus, typically around the level of the cricoid cartilage in adults. At rest it maintains a tonic high pressure to prevent air entry and reflux from the esophagus.

Functionally, the pharyngoesophageal segment acts as a gateway during swallowing. When a bolus is swallowed, neural reflexes cause the cricopharyngeus (UES) to relax and the segment to open, allowing transit into the esophagus. After bolus passage, it closes to restore guard against air ingress and reflux. Proper timing and coordination with pharyngeal and esophageal motility are essential for efficient deglutition and airway protection.

Clinical significance includes disorders of the pharyngoesophageal segment such as cricopharyngeal dysfunction or hypertensive UES, which can cause dysphagia and a sensation of fullness or a lump in the throat. Zenker’s diverticulum, a pulsion diverticulum, often develops at Killian’s dehiscence in this region and can present with regurgitation, dysphagia, or halitosis. Evaluation commonly involve videofluoroscopic swallow studies or manometry; treatment options range from dilation and botulinum toxin injections to cricopharyngeal myotomy or endoscopic myotomy. See also upper esophageal sphincter and Zenker’s diverticulum for related concepts.