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.