12-10. Traveling Wave on the Basilar Membrane
Figure 12-10. Displacement of the basilar membrane by a traveling wave set up when the stapes vibrates sinusoidally. The distance from the basal end is denoted as x, measured in millimeters. The propagation velocity and wavelength decrease as the wave moves to the right onto less stiff parts of the basilar membrane. The main peak occurs at the region of the membrane that is in resonance at the frequency of the impressed wave. The amplitude diminishes rapidly to the right of that point. The dotted line is the envelope of the wave, that is, it traces out the positions that the maxima of the traveling wave sweep out. The figure is only qualitatively accurate.
© William J. Mullin