Behavior of the basilar membrane with pure-tone excitation.

Three successively more elaborate models for the fluid‐elastic interaction in the cochlea are analyzed by asymptotic methods, with which an a priori assumption of “long” or “short” wavelengths is not necessary. Appropriate stiffnesses are estimated from Bekesy's static‐point and pressure‐load measurements. The last model admits an independent motion of the arches of Corti and the remaining portion of the basilar membrane. Results indicate that the maximum arch displacement does occur about 5 mm closer to the stapes than the maximum basilar‐membrane displacement, which seems to provide an explanation for the difference in “place” according to Bekesy's observation and damage evidence. Furthermore, the calculated results for the phase agree remarkably with Bekesy's observation for low frequency and with the recent observations by Rhode for high frequency.