Motions of the posterior pharyngeal wall in swallowing.

The motions of the posterior pharyngeal wall during swallowing were studied in four asymptomatic males using a new method for videoradiography. Radiopaque markers of 4 mm diameter were affixed to the pharyngeal wall by suction. Ventrodorsal and axial components of motion were measured frame by frame. Large axial motions occurred during the pharyngeal stage of swallowing. Cephalad displacement of each marker occurred early and was followed by caudad motion. Within the pharyngoesophageal segment, there were cephalocaudal motions measuring as much as 25 mm. A late caudad motion beyond the reference position was observed in this segment in two participants. This late motion may play a role in passing the bolus through the pharyngoesophageal segment. The findings support the concept of an "engulfment" mechanism in pharyngeal kinesiology.