Cricopharyngeal achalasia results from poor coordination of pharyngeal peristalsis with incomplete relaxation of the upper esophageal sphincter. The upper one-third of the esophagus is composed of skeletal muscle; therefore, any process that impairs the function of skeletal muscle or neuromuscular conduction may produce cricopharyngeal achalasia.

Radiographically, incomplete relaxation of the cricopharyngeus produces a smooth posterior impression on the esophagus at the C5-6 level. This impression is sometimes referred to as a cricopharyngeal bar. Such an impression is often seen in asymptomatic patients, although it is still an abnormal finding. Progressive involvement leads to varying degrees of dysphagia. Severe disease may result in penetration of pharyngeal contents into the laryngeal vestibule or in frank aspiration. Cricopharyngeal myotomy is performed in severe cases.

Cricopharyngeal achalasia has been suggested as a factor in the formation of Zenker's diverticula. Increased pressures at and above the upper esophageal sphincter are thought to create a pulsion diverticulum at an area of natural relative weakness in the posterior aspect of the cricopharyngeus, Killian's dehiscence.

After total laryngectomy, bunched residual fibers of the cricopharyngeus sometimes create a posterior impression on the neopharynx identical to that seen in cricopharyngeal achalasia. These should not be mistaken for recurrent tumor.

REFERENCE: Eisenberg, Gastrointestinal Radiology, pp. 5-8