Immunohistochemical approach for the investigation of nerve distribution in the shoulder joint capsule.

Twenty six shoulder joint capsules obtained from 13 autopsy cases were studied to evaluate the nerve distribution using immunohistochemical techniques. Immunohistochemical staining of polyclonal S-100 protein or protein gene product 9.5 was more sensitive, specific, and reproducible compared with conventional gold chloride methods. A small number of clustered nerve fibers were found in the superficial layer, and many nerve fibers with large diameters were found in anteroinferior portions of the deep layer. Nerve fibers of various sizes were more numerous in posterosuperior and anterosuperior portions of the boundary zone between labrum and capsule. A Pacinian corpuscle was clearly recognized in a capsule. In the central portion of the long head of some biceps brachii tendons, relatively large nerve fibers continued from capsules. The results suggest that the capsule and long head of the biceps brachii tendon may play a partial role in the stability of the shoulder joint through afferent feedback.