The tympanic membrane as a part of the middle ear transformer.

Time-averaged holography, an optical interference method, allowed us to obtain, for the first time, complete displacement patterns of the tympanic membrane of cat and man in response to sound. The findings are compatible with the concept of the “mechanism of curved membranes” originally proposed by Helmholtz (1868), which implies that an important part of the transformer mechanism of the middle ear resides in the tympanic membrane itself.