A human right ear
A tympanometer is a medical measuring instrument that measures the motility of the mucous membrane as a function of pressure in the ear canal (tympanometry). This is only possible if there is no hole in the mucous membrane. A tympanometer is used to determine whether there is a middle ear infection.
The measurement method consists in lowering a tone in the ear canal and measuring the reflection. A widely used frequency is 220 Hz at a sound intensity of approximately 65 decibels (flux level). During this tone, this negative pressure is varied from a minimum of 40 cm water pressure via zero to plus 20 cm water pressure. This measurement gives an impression of the meticulousness or stiffness of the mucous membrane.
In a normal mucous membrane, reflection at a negative pressure and upper pressure will be maximal and at the pressure zero will be minimal.
This is comparable to tearing up a drum sheet, with the drumstick no longer able to spring back to a loose sheet, and if the sheet is pressed, or tensioned. Also see
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