PARAMETERS FOR MODELING THE UPPER EXTREMITY

The purpose of this paper was to provide parameters for the developmen t of a musculoskeletal model of the upper extremity. Five upper extrem ity specimens were obtained from four fresh cadavers. Anthropometric m easures were obtained for each cadaver. Segment inertial parameters we re estimated for each specimen from anthropometric measures of the cad aver from which the specimen was obtained. The three-dimensional kinem atics of the humerus, ulna, and radius in different movements of the g lenohumeral, humeroulnar and ulnoradial joints were measured for each specimen using of the 3Space(TM) tracking system (Isotrack, PoIhemus). The instantaneous rotation center of the glenohumeral joint and the i nstantaneous rotation axes of elbow flexion and forearm pronation were determined for each specimen from the kinematic data. The specimens w ere dissected and the muscle origins and insertions and bony structure s needed in upper extremity modeling were digitized using the 3Space(T M) system. The shapes of muscle origins and insertions were estimated. Muscle length, volume and pennation angle were measured for the estim ation of physiological cross-sectional areas of each muscle. The resul ts, which are given for one specimen, showed that the rotation center of the glenohumeral joint was very close to the geometric center of th e joint with a mean distance of 4 mm. The mean angle between the flexi on-extension and pro-supination axes of the elbow joint was 94 degrees . The minimum distance between these two axes was about 4 mm. (C) 1997 Elsevier Science Ltd.