1986 Volume 1986 Issue Supplement3 Pages 67-75
The relationship between mucociliary and muscular clearance in the eustachian tube was investigated. To test clearance function for the tube, colored fluids of varying viscosities and volumes were injected into in the tympanum of cats. Displacement of the fluid through the tube was observed endoscopically. The interval between the instillation and beginning of discharge of the fluid from the pharyngeal orifice of tube was measured. Clearance time was prolonged with fluids having high viscosities. To test muscular clearance, the tensor veli palatini muscle was stimulated electrically. to simulate swallowing, and the number of contractions necessary for massive discharge of the fluid was counted. Massive discharge occurred only with low viscosity fluid placed in the tympanum, whereas small amouts of highly viscous fluid were cleared by linear discharge. We concluded that when the volume of middle ear effusion was small, the fluid was cleared by mucociliary clearance. When the volume of fluid was large, the low viscosity fluid was cleared by muscular clearance only, while highly viscous fluid was cleared both by ciliary and muscular clearance.
