[Analysis of the human wrist motion in three dimensions using a video-digitizer]

We report the results of a new assessment system (using a Video-digitizer and non-contact type transducer) in order to clarify the three-dimensional human wrist motion. The results of basic experimental studies conducted prior to this clinical assessment indicated that this new system was an extremely reliable and useful to measure three-dimensional motion. The results of the wrist motion in normal individuals showed supination at radial flexion movement, pronation in ulnar flexion movement, and pronation in the dorso-ulnar part of rotational movement. The comparative results of human wrist motion in pathological conditions suggested that an involvement of the distal radio-ulnar joint was primarily responsible for impairment in the rotational movement of the human wrist.