NEURAL ANATOMY OF THE GLENOHUMERAL LIGAMENTS, LABRUM, AND SUBACROMIALBURSA

The neural histology of the human shoulder ligaments, glenoid labrum, and subacromial bursae were studied using a modified gold chloride sta in. Two morphological types of mechanoreceptors and free nerve endings were found in the Ligaments. Slow adapting Ruffini end organs and rap idly adapting Pacinian corpuscles were identified in the superior, mid dle, inferior, and the posterior glenohumeral ligaments. These special ized proprioceptive nerve endings were also found in the coracoclavicu lar, and coracoacromial ligaments. Only free nerve endings were found in the glenoid labrum and these were located in the peripheral half. S cattered free nerve endings were found throughout the subacromial burs ae. This is the first histological evidence of neural receptors in the human shoulder ligaments, glenoid labrum, and the subacromial bursae. Any disruption of the labrum or these ligaments by trauma or surgery can deprive the shoulder of mechanical stability, and may cause a decr ease in proprioception because of the loss of these afferent neural re ceptors. Removal of symptomatic, inflamed bursae may decrease pain sig nals from this area of the shoulder.