Quantitative analysis of neural distribution in human coracoacromial ligaments

This study investigated sensory nerve distribution in 27 human coracoacromi al ligaments by immunohistochemical methods using antiprotein gene product 9.5 antibody and anticalcitonin gene related peptide antibody. Mean nerve d ensities mere compared among three areas (acromion side, center, and coraco id side) in two groups (patients with rotator cuff tears and patients with shoulder dislocations), In all three areas of both groups, many nerve fiber s immunoreactive to antiprotein gene product 9.5 antibody were observed in the periligamentous bursal tissue, However, in the ligament parenchyma, ner ve fibers immunoreactive to antiprotein gene product 9.5 antibody were reco gnized only around blood vessels, Nerve fibers immunoreactive to anticalcit onin gene related peptide antibody were recognized in the periligamentous b ursal tissue. However, in the ligament parenchyma, there were no nerve fibe rs immunoreactive to anticalcitonin gene related peptide antibody, Nerve de nsity of the rotator cuff tear group, as revealed by both immunostainings, showed a significant increase compared with that of the shoulder dislocatio n group in all three areas. The results of this study show that it is possi ble the increase in sensory nociceptive nerve fibers in the coracoacromial ligaments may be one of the causes for pain in patients with rotator cuff t ears.