THE SENSORY INNERVATION OF THE SHOULDER JOINT OF THE MOUSE

The ultrastructure and location of sensory nerve endings in the should er-joint capsule, its tendinous reinforcements and in the periarticula r connective and muscle tissue have been studied by means of light and electron microscopy in adult female white NMRI-F, laboratory mice, ag ed 2.5 - 13 months. Most of the sensory nerve endings were detected in the fibrous layer of the joint capsule or in the inserting tendons. T he identified lamellated corpuscles of the Pacini type are small and s ometimes associated with Golgi tendon-organs. Large Vater-Pacini corpu scles were not detected. Ruffini corpuscles are found in small numbers only in the moderately dense connective tissue of the joint capsule. Golgi tendon organs were found mainly at the muscle-tendon junction of the muscles surrounding the joint. Muscle spindles have been identifi ed mainly in periarticular muscles close to the muscle-tendon junction s. The number and distribution of the different types of mechanorecept ors investigated in the present study suggest that periarticular corpu scular sensory nerve endings play an important role in shoulder-joint control and mobility. The occurrence of small uniformly shaped lamella ted corpuscles of the Pacini type in qualitatively different areas of surrounding tissue implies that they are susceptible to different kind s of mechanical stimuli.