A simple box model of the cochlea consists of two fluid chambers separated by the BM. The longitudinal coordinate, , goes from the left, base, to the right, apex, and an external pressure is applied on the left side (by the stapes) to represent vibration transmitted from the ossicles. The two fluid chambers, SV and ST, are separated by a flexible BM, which occupies part of the cochlear partition width, and connect to each other at the end of the model via the helicotrema, where the pressure difference between the two chambers is zero.
