Contraction Response to Muscle Percussion: Physiology and Clinical Significance

Abstract

THE contraction of normal skeletal muscle upon direct percussion was noted in early descriptions of the muscle reflexes, 1,2 but the mechanism of this response has been poorly understood. Babinski and Jarkowski 3 and Tromner 4 distinguished this response from a reflex and observed that it may be present when reflexes are lost, as in polyneuritis. However, Wartenberg 5 equated muscle percussion with the percussion of the tendon and the periosteum and considered the contraction response in each instance to be a reflex due to muscle stretch. In the present investigation, the physiology of the contraction response to muscle percussion was studied in order to understand the changes in this response that are observed in neurologic disorders. Methods Observations were made on human subjects and on rabbits. The human subjects were six normal adults, three neurologically normal patients undergoing spinal anesthesia, four patients with peripheral neuropathy, and two patients