In this study, we conducted physical therapy sessions for a patient with right hemiparesis following cerebral infarction, who had difficulty washing the left arm with the right hand due to impaired flexion movement of the right elbow. During the treatment sessions, we attempted to correct the subject’s sitting posture and provided body-washing activity training to promote effective right elbow flexion. We observed that the subject had difficulty in reaching the left arm with the right hand, and no improvement was observed in the body-washing activity. We evaluated the tone of the biceps muscle (the primary elbow flexor) on the right side using a muscle tonus test. The proximal biceps was shortened and hypertonic, the muscle belly was hypotonic, and the distal biceps was normotonic. We hypothesized that the hypertonia and shortening of the proximal biceps on the right side modified the afferent activities of the hypotonic muscle belly by extending it during attempted elbow flexion. Passive stretching was performed to decrease the hypertonia and lengthen the proximal biceps on the right side. This resulted in restoration of the tone of the muscle belly and improvement in right elbow flexion. In addition, electromyography demonstrated improvement of muscular activities in the muscle belly of the right biceps. Thus, an improvement was noted in the elbow flexion range on the affected side and the patient was able to wash the left arm with the right hand. The present case suggests the necessity of evaluating the muscle tone of different parts of a single muscle when evaluating abnormal muscle movements.
