KINEMATIC AND DYNAMIC CHARACTERISTICS OF SOLID PELLET MOVEMENT DURINGTHE PHARYNGEAL PHASE OF SWALLOWING

Information on solid particle movement through the pharynx, in additio n to its physiologic importance, has relevance to the swallowing of me dications in pill form. The purpose of this study was to determine the kinematics of a solid particle during the oral-pharyngeal phase of sw allowing. We used a concurrent manometric-videofluoroscopic technique and identified two distinct zones of increasing bolus velocity, one at the tongue base and the other at the pharyngo-upper esophageal sphinc ter (UES) region. Velocity de creased significantly (p <.05), to 9.0+/ -1.0 cm/s, while the bolus traversed the area located between the tip of the horizontal epiglottis and the pharyngeal wall. The velocity of the liquid barium bolus head was similar to that of the solid barium p ellet. The average bolus tail velocity was relatively constant. The ac celeration of the barium pellet was temporally associated with develop ment of an incrementally decreasing pressure distal to the location of the pellet in the hypopharynx and across the UES. In conclusion, the kinematics of a solid particle are similar to those of the head of a l iquid bolus, but both are different from bolus tail kinematics. During the pharyngeal phase of swallowing, the area located ahead of the bol us exhibits an incrementally decreasing pressure, caudally. This may f acilitate bolus transport and contribute to airway protection.