FIG. 2.

Schematic diagrams of the experimental setup in forward (A) and reverse drive (B). The laser beam produced by a laser Doppler vibrometer (LDV) was almost perpendicular to the BM. The angle between the laser beam at the incus tip and the direction of footplate movement was approximately 50–60 °; the angle between the laser beam at the RWM and the normal moving direction of RWM was approximately 60–70 °.