Fig. 1.

Schematic drawing of the experimental setup.A, Slots proportional to finger length (right) were cut in a piece of black cardboard (left) that then was placed in a vertical frame (arrow). When the subject placed each fingertip in the center of its own slot (as in B), these slots made the range of flexion–extension movements proportional to the size of each subject's fingers. B, Finger movements were recorded simultaneously with (1) a video camera mounted orthogonal to the plane of the cardboard frame (left) and (2) an instrumented glove worn by the subject (right).