Currently the evaluations of upper extremity motion have relied on a task-oriented approach to gain an accurate clinical picture of the functional capacities. As it is, an adequate and objective system to estimate upper extremity function is yet to be developed.

Authors used the virtual reality motion analysis system(VRMAS) which was developed by us for the purpose of investigating the kinematics of upper extremity motion during drinking a cup of water. Four healthy male adult subjects were recruited from the hospital personnels. After each subject sat down on a chair resting against the backrest in a neutral position, in front of a table he was instructed to drink the content of the cup from the table.

The data was analized and showed the following results. While drinking, the hand movements were smooth and linear. There were six distinct stages during drinking a cup of water; a reaching for the cup(stage 1), picking up the cup and carrying the cup to the mouth(stage 2), extending neck and drinking from the cup(stage 3), flexing neck(stage 4), replacing the cup to the table(stage 5), and returning to the start position(stage 6). During the stage 1 and 2, of all joint motions, the shoulder adduction and elbow flexion were most prominent. The stage 3 showed the most complex movements in shoulder flexion, forearm pronation, and wrist extension which were simultaneous. Remaining stages were the reversal of the first three stages. We could observe the ranges of motion of neck, shoulder, elbow, and wrist joint as well as the relationships of these joints at the same time.

In conclusion, VRMAS could be a very useful evaluation tool for the upper extremity motion and for obtaining the kinematic data from the upper extremity motion analysis.