Outer hair cells (OHCs) were subjected to three different hypo‐osmotic challenges which induced shape changes in OHCs. The longitudinal and circumferential strains, εzand εc, respectively, were extracted from a morphometric analysis of video images of the cells. A value of εz/εc=−0.72 was obtained and was found to be independent of the applied osmotic gradient. Using an elastic isotropic membrane model for the OHC lateral wall, the ratio of the elastic shear modulus μ to the elastic area expansion modulusKwas calculated yielding a value of 0.054. The contribution of this ratio to OHC mechanics is discussed.