The cricopharyngeus revisited.

The motor function of the pharyngo-oesophageal (PO) segment during swallowing in terms of tonicity, relaxation and peristalsis was evaluated in 25 patients with a posterior cricopharyngeus impression. Functional abnormalities were common. Defective tonicity was present in 11 patients. Relaxation was normal in all patients except at the level of the cricopharyngeal muscle. Abnormal peristalsis was present in 19 patients as weakness, paresis or abnormal timing. The impression of the cricopharyngeus was effaced during the late stage of swallowing due to collapse proximal and distal to the cricopharyngeus. It was not due to successive distension at the level of the cricopharyngeus. In 11 patients there was some retention of barium proximal to the cricopharyngeus after the passage of the barium bolus. This was due to weakness in the inferior pharyngeal constrictor and/or an abnormal timing of the peristalsis whereby contraction of the cricopharyngeus occurred before peristalsis in the inferior pharyngeal constrictor had cleared the pharynx of barium. The observations indicate that bulging of the cricopharyngeal muscle is only one aspect of a profoundly altered motor function of the PO segment.