Bolus aggregation in the oropharynx does not depend on gravity.

OBJECTIVE

To determine whether bolus aggregation in the oropharynx (before swallowing) depends on gravity.

DESIGN

Before-during trial, with subjects serving as their own controls.

SETTING

Hospital radiology suite.

PARTICIPANTS

Five asymptomatic adult volunteers.

INTERVENTIONS

Videofluorography was performed while subjects ate soft and hard foods containing barium, first seated upright and then kneeling face down (quadruped position).

MAIN OUTCOME MEASURES

Duration of food processing in the oral cavity, bolus aggregation in the valleculae, and pharyngeal swallow.

RESULTS

Transport of chewed solid food from the oral cavity to the oropharynx (stage II transport) typically started several seconds before onset of swallow, regardless of head position or initial food consistency. Bolus aggregation in the valleculae (between the epiglottis and the tongue) began an average of 1.7 +/- 2.5sec before the onset of the pharyngeal swallow (p < .001). Stage II transport was driven by tongue-palate contact.

CONCLUSIONS

Transport of chewed solid food from the oral cavity to the pharynx is driven actively by tongue-palate contact and does not depend on gravity. A bolus may accumulate in the valleculae for several seconds before the swallow.