The role of the spiral ligament in cochlear mechanics.

Maximum deflection of the basilar membrane (BM) in fresh guinea pig cochlea preparations attains values attaining roughly half the width of the membrane. Displacement of the BM is made possible by the elastic spiral ligament, which participates directly in dynamic processes of cochlear mechanics. That the movement is transmitted to the spiral ligament during experimental deformation of the BM by an instrument is borne out also by structural changes in the lateral wall epithelium in acoustic trauma and by vascular changes produced by chronic acoustic stress.