Peristalsis in pharyngeal constrictor musculature in relation to positioning and gravity

The motor activity of the pharyngeal constrictors in terms of peristalsis and protrusion depths was studied cineradiographically in 15 non-dysphagic volunteers in three positions: sitting, right decubitus horizontal, and head-down 30 degrees, during swallowing of a 10 ml bolus of thin liquid barium. Using a frame rate of 50/s the speed of peristalsis was calculated by frame counting. The speed of peristalsis and the depth of protrusion of the constrictor wall did not depend on the direction of gravity force in relation to the long axis of the pharynx. Neither the position of the hyoid bone nor its movement during pharyngeal swallowing changed in relation to position and gravity. Pharyngeal activity during swallowing in normal individuals is fairly stable and does not change in relation to gravity.