Mechanical properties of basilar membrane.

A fresh basilar membrane has different mechanical properties in the radial and in the longitudinal directions. When pressure with a needle is exerted on the basilar membrane, a narrow radially oriented strip is deflected. The form of the deflection can be deduced from the pathological consequences of the acoustic trauma as well. The observed anisotrophy is a property of the vital membrane and is disturbed by chemical and physical influences and is lost post mortem. The post-mortem changes can explain the results obtained by von Békésy which differ from ours. The physiological meaning of the mechanical properties of the basilar membrane is discussed here.