NONNOXIOUS STIMULATION OF THE GLENOHUMERAL JOINT CAPSULE ELICITS STRONG INHIBITION OF ACTIVE SHOULDER MUSCLES IN CONSCIOUS HUMAN-SUBJECTS

Information about the function of joint afferents in humans is scarce. Therefore, we investigated the influence of non-noxious electrical st imulation of the glenohumeral joint capsule on the activity of shoulde r muscles in conscious human subjects. Stimulation electrodes were ins erted in the joint capsule during arthroscopy. Only when the anterior inferior part of the capsule including the glenohumeral ligament was s timulated a strong and rather long latent general inhibition in volunt arily activated shoulder muscles was observed (average latency and dur ation: 33 ms and 76 ms, respectively). The inhibition was followed by an excitation and a few but inconsistent oscillations in the muscle ac tivity. The results suggests a potent proprioceptive feedback pathway for the motor control of the human shoulder joint. However, further in vestigations are needed to clarify the involvement of several possible afferent pathways (C) 1998 Elsevier Science ireland Ltd. All rights r eserved.