[Clinical analysis of motion using multimedia technology]

In disabling orthopaedic and neurological disorders, in addition to clinical and imaging examination, observation of the motion is an important method of examination. It serves as a starting point for the motion analysis using digital video. In this way, muscle functions can be measured with the aid of a kinesiological EMG. Load on the joints of the lower extremities can be deduced from a projection of the foot reaction vector on the body. Combination of a video film of the motion (the gait) with measurement of the kinesiological EMG provides a motion analysis based on multimedia techniques. With modern personal computers, interactive examination of these digital data is simple. Three examples of this functionality can be viewed at the Internet site of this journal (http:@appendix.niwi.knaw.nl): the normal walking cycle, the active stabilization of the knee after an injury of the anterior cruciate ligament and the gait of a woman with cerebral palsy before and after orthopaedic surgery. Motion analysis using multimedia techniques makes it possible to analyse relationships between muscular and articular functions on the one hand and impaired motion on the other in a way that is meaningful to the clinician.