Deglutitive tongue action: Volume accommodation and bolus propulsion

Background: Swallow function is best analyzed in components because discrete component failure may be compensated for with devised maneuvers, postures, or biofeedback techniques. The present investigation examined normal deglutitive tongue function. Methods: Biplane videofluoroscopy synchronized with intraluminal manometry was performed in eight volunteers. Tongue surface motion was characterized as centripetal or centrifugal along seven equiangular rays emanating from the tongue center during 1-, 5-, 10-, and 20-mL swallows. Results: The tongue perimeter remained in contact with the alveolar ridge while the central groove exhibited centripetal and subsequent centrifugal motion that, in conjunction with the pharyngeal walls, created an oropharyngeal propulsive chamber and then expelled that chamber's contents into the hypopharynx. Intrabolus propulsive pressure was generated when the initially expansive propulsive chamber volume contracted to the test bolus volume. Because pharyngeal chamber action cycle timing was relatively constant among bolus volumes, vigorous expulsion occurred with large volumes but relatively delayed, sluggish expulsion occurred with smaller volumes. Conclusions: Deglutitive tongue functions include bolus containment, volume accommodation, and the major contributor to bolus propulsion.