Glenoid labrum study. Anatomic and histologic implications in Bankart repair

Abstract

Glenohumeral joint particular anatomy and biomechanics raise many questions about its implication in the aetiology and pathophysiology of shoulder instability. We proposed ourselves to perform an anatomic and histologic study of the nervous endings and receptor structures inside the glenoid labrum emphasizing the anatomic and neurophysiologic importance of treating Bankart lesions. We performed minute anatomic dissections and harvested glenoid labrum from 47 fresh cadavers with no lesions of the shoulder, at the Anatomy Department of the University of Medicine and Pharmacy from Craiova; we studied micro anatomic the stereo topography of the nervous endings and receptor structures using the Cajal-Nonidez argentic impregnation staining method and we examined the serried section at a Nikon research microscope. We also made in vivo observations of the labrum morphology during shoulder arthroscopy. Our observations revealed: spiral neurofibers and Pacini lamellar corpuscle at the posterior and inferior aspect of the glenoid labrum; grouped neurofibers first described by Rollette at the anterior and superior aspect; encapsulated nervous endings type II (A, B) from Freeman and Wyke classification at the junction area between the labrum and the long biceps tendon. The presence of mechanic receptors inside the glenoid labrum and especially at the insertion of long biceps tendon brings up the idea for the existence of some neuron modulating processes associated to movements with the nervous center at C5-C7 cervical neuromeres. The presence of mechanic receptors inside glenoid labrum opens new perspectives in the knowledge of neurocibemetics mechanisms involved in shoulder joint complex motions; it also emphasize the importance of Bankart repair followed by functional therapy in order to restore and to retrain the damaged proprioceptive reflexes.