| Description |
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The middle ear cleft is essentially a noncollapsible gas filled body cavity which communicates intermittently with the outside atmosphere through the Eustachian tube.
The Eustachian tube is normally closed, but it opens several times a minute for brief intervals during swallowing or yawning.
These brief and repetitive openings allow the equalization of middle ear pressure with the ambient atmospheric air pressure and permit a partial exchange of the gaseous contents of the middle ear cleft, thereby maintaining the ambiance of the gas within the middle ear with respect to both pressure and composition.
During each act of swallowing, i.e., each Eustachian tube opening, 1 microlitres of air enters the middle ear. |
