Negative pressure in the middle ear by ciliary propulsion of mucus through the eustachian tube.
Mucus was placed in the middle ears of 11 cats. A needle and stop-clock placed in the bulla communicated with the tympanic cavity. The pressure changes in the needle were transcribed on a flowing graph via a transducer in communication with the stop-clock. Negative pressure developed in each test ear. The average maximum negative pressure was 12 mm Hg  with a minimum of 2 mm Hg and maximum of 24 mm Hg. The peak negative pressure, reached in 30 to 60 min. in most ears, occurred in 10 min. in one and in 3 hrs. in another. The qualitative results show all ears developed a negative pressure when mucus was in the tympanic cavity. The quantitative data suggest an average maximum negative pressure of 12 mm Hg reached at about 1 hr.
D000818:Animals; D002415:Cats; D002923:Cilia / Q000502:physiology; D004427:Ear Diseases / Q000628:therapy; D004432:Ear, Middle / Q000503:physiopathology*; D005064:Eustachian Tube / Q000503:physiopathology*; D008954:Models, Biological; D009093:Mucus; D011312:Pressure; D014432:Tympanic Membrane / Q000503:physiopathology