The present investigation was undertaken to identify the presence, the localization and the types of mechanoreceptors in the canine glenohumeral ligaments and in the surrounding tissue with the aim to give further knowledges for a better understanding of the shoulder instability. Medial and lateral glenohumeral ligaments of both sides from six canine cadavers were obtained at necroscopy. The ligaments were stained in bulk by using the gold chloride method modified by Zimny, paraffin-embedded and cut at 50 μm in thickness. Three morphologically distinct mechanoreceptors were identified: two slowly adapting receptors (Ruffini endings and Golgi tendon organ-like receptors) and one quickly adapting receptor (Pacinian corpuscles); in addition free nerve endings were observed. The most abundant mechanoreceptors found in the shoulder ligaments were the Ruffini endings. All the receptors are mainly localized at each end of the ligaments, and prevalently in their glenoid portion. In particular, in the MGL the highest density was at the cranial site of insertion into the scapula. All these types of sensory nerve endings were more numerous in the MGL. The presence of a variety of mechanoreceptors in the canine glenohumeral ligaments is unequivocal evidence that these ligaments provide the CNS with information regarding their mechanical states. Slowly adapting receptors identify motion and position of ligament, allowing the CNS to interpret the position and angle of rotation of the joint; quickly adapting receptors can detect the acceleration and deceleration applied to the ligament at the beginning and end of the movement. Free nerve endings act as pain receptors. The presence of a greater number of slowly adapting receptors suggest that the sensation of position and movement of the ligaments plays an important role in the kinetics of the shoulder joint; whereas the less abundant quickly adapting receptors can support the hypothesis that this joint is subjected to a lower acceleration or deceleration as regards the other forelimb joints. Furthermore, the present investigation showed that most of the mechanoreceptors were located in the glenoid portion of the ligaments; these observations lead us to suppose that this end of the glenohumeral ligaments is the site which is more sensitive to mechanical stimuli.
Mechanoreceptors in the canine glenohumeral ligaments: their role in the shoulder stability.
GRANDIS, ANNAMARIA;BOMBARDI, CRISTIANO;SPADARI, ALESSANDRO
2004
Abstract
The present investigation was undertaken to identify the presence, the localization and the types of mechanoreceptors in the canine glenohumeral ligaments and in the surrounding tissue with the aim to give further knowledges for a better understanding of the shoulder instability. Medial and lateral glenohumeral ligaments of both sides from six canine cadavers were obtained at necroscopy. The ligaments were stained in bulk by using the gold chloride method modified by Zimny, paraffin-embedded and cut at 50 μm in thickness. Three morphologically distinct mechanoreceptors were identified: two slowly adapting receptors (Ruffini endings and Golgi tendon organ-like receptors) and one quickly adapting receptor (Pacinian corpuscles); in addition free nerve endings were observed. The most abundant mechanoreceptors found in the shoulder ligaments were the Ruffini endings. All the receptors are mainly localized at each end of the ligaments, and prevalently in their glenoid portion. In particular, in the MGL the highest density was at the cranial site of insertion into the scapula. All these types of sensory nerve endings were more numerous in the MGL. The presence of a variety of mechanoreceptors in the canine glenohumeral ligaments is unequivocal evidence that these ligaments provide the CNS with information regarding their mechanical states. Slowly adapting receptors identify motion and position of ligament, allowing the CNS to interpret the position and angle of rotation of the joint; quickly adapting receptors can detect the acceleration and deceleration applied to the ligament at the beginning and end of the movement. Free nerve endings act as pain receptors. The presence of a greater number of slowly adapting receptors suggest that the sensation of position and movement of the ligaments plays an important role in the kinetics of the shoulder joint; whereas the less abundant quickly adapting receptors can support the hypothesis that this joint is subjected to a lower acceleration or deceleration as regards the other forelimb joints. Furthermore, the present investigation showed that most of the mechanoreceptors were located in the glenoid portion of the ligaments; these observations lead us to suppose that this end of the glenohumeral ligaments is the site which is more sensitive to mechanical stimuli.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
