HISTOMORPHOLOGICAL FINDINGS ON PROPRIOCEPTION IN THE SHOULDER

Purpose of this study was the evaluation of distribution and morpholog y of mechanoreceptors in the glenohumeral joint capsule and rotator cu ff in comparison to the coracoacromial ligament by means of specific i mmunfluorescence microscopy. The complemente joint capsules, rotator c uffs and coracoacromial ligaments of three fresh cadaver shoulder were harvested. Serial cryostate sections were taken and alternately incub ated with antiserum against neurofilament, lamin or myelin of peripher al nerves. The antibody-reaction was visualized with fluorescin Ig-G. The nerve endings were photographed and computer-aided 3-dimensional r econstructions were performed. Three types of corpuscular and free ner ve endings of different morphology were found in different distributio ns: whereas the Ruffini corpuscles were much more frequent in the cora coacromial ligament and rotator cuff, Pacini endings were predominantl y found in the joint capsule. Generally corpuscular nerve endings were more frequent in the coracoacromial ligament and the rotator cuff tha n in the antero-inferior capsule and the number of corpuscles increase d from medial to lateral within the anterior and inferior parts of the capsule. The dense ligamentous tissue was almost aneural whereas the periarticular fatty or loose connective tissue contained nerve fibres and nerve endings. In view of the results of other experimental and cl inical studies the high frequency of Ruffini and Pacini endings in the rotator cuff and coracoacromial ligament suggest, that both are invol ved in the neurosensory control of glenohumeral stability and subacrom ial impingement. In contrast our findings in the joint capsule do not clearly proove, that those joint receptors predominantly maintain join t stability.