The cricopharyngeus is a sling-shaped muscle that forms part of the upper esophageal sphincter, between the throat and the esophagus. It is located behind the larynx (voice box). The cricopharyngeus muscle is contracted during the normal resting state, and it relaxes during swallowing. The forward and vertical movement of the larynx during swallowing also contributes to opening of the upper esophageal sphincter. When there is a problem with the way the cricopharyngeus relaxes or with opening of the upper esophageal sphincter, cricopharyngeal dysfunction is diagnosed.
There are many causes of cricopharyngeal dysfunction, including reflux disease, stroke, neuromuscular diseases, radiation therapy, and post-surgical changes. At times, a cause can not be identified, and the cricopharyngeal dysfunction is referred to as idiopathic. The most common types of cricopharyngeal dysfunction are hypertonicity (pressure too high), delayed relaxation, or incomplete relaxation. These disorders are diagnosed with a combination of barium swallow studies and pharyngeal manometry. Such cricopharyngeal disorders can frequently be treated with dilation and botulinum toxin (Botox) injections.