Inferior Pharyngeal Constrictors in Tracheoesophageal Phonation

It has been suggested that the pseudoglottis in tracheoesophageal (TE) and esophageal phonation is formed by the activity of the inferior pharyngeal constrictor muscles. However, the physiology of these muscles has not been entirely investigated in laryngectomized patients. In the present study, the behavior of the pharyngoesophagus in eight TE speakers were investigated during swallowing, phonation and rest. Video-fluoroscopy revealed a single mucosal fold in the posterior wall of the PE segment in the resting state, as well as in phonation, which partially disappeared and dilated the pharyngoesophagus during swallowing. During phonation, the “pseudoglottis” was formed in the upper part of the mucosal fold. On the other hand, the lower part of the fold dilated and did not participate in the formation of the pseudoglottis. Intraluminal pressure-monitoring of the pharyngoesophagus was performed using four subjects. In three of the four subjects examined, the “high pressure zone” was present just below the level of the pseudoglottis at rest, and the pressure was lowered during phonation and swallowing. It was suggested that the pseudoglottis was formed by the activity of the thyropharyngeus muscle, and that the high pressure zone was formed by the constriction of the cricopharyngeus muscle. During phonation, the suppression of the cricopharyngeus muscle activity seemed to be effective for dilating the high pressure zone and lowering the airway resistance.