ACR Codes: 7.1
The pharyngoesophageal segment (PES) is the radiographic equivalent of the manometrically defined upper esophageal sphincter (UES). The PES lies at the junction of the hypopharynx and cervical esophagus. The UES is tonically contracted at rest. Initiation of swallowing causes the sphincter to relax ahead of the oncoming bolus. The UES also acts as part of the pharyngeal peristaltic wave, functioning in sequence with the constrictor musculature. The PES is best evaluated during dynamic recording of the pharynx in an upright lateral projection.
In most asymptomatic patients, the cricopharyngeus is not seen as barium passes through the open PES. However, a prominent cricopharyngeus is detected on barium studies in about 5% of asymptomatic individuals as a smooth, 1-cm bar-like protrusion of the posterior pharyngeal wall into the barium column in the lateral projection. Cricopharyngeal prominence in asymptomatic patients is of unknown clinical significance, but may be related to undetected gastroesophageal reflux.
Some patients who demonstrate a prominent cricopharyngeus have dysphagia or complain of a "lump in the throat." The cricopharyngeus may show delayed opening, incomplete opening, or early closure. In symptomatic patients, a prominent cricopharyngeus may be due to pharyngeal paresis or occur as a compensatory response to gastroesophageal reflux or esophageal obstruction (Table 1). In the past, a prominent cricopharyngeus has been termed "cricopharyngeal achalasia." This is a misnomer.
Esophageal obstruction (functional or mechanical)
Film .2 also shows a pseudo-Zenker's diverticulum (arrowhead). This is a small collection of barium above a prominent cricopharyngeus. This does not represent a true Zenker's diverticulum, but changes size, and empties following swallowing.