肩袖及肩关节囊的神经组织学研究及临床意义

The neurohistology of the rotator cuff and capsule of shoulder

目的通过对正常肩袖及肩关节囊神经力学感受器分布特点的研究,阐明维持肩关节稳定的解剖结构的神经组织学基础。方法采用改良银染法和S-100免疫组织化学染色方法、借助计算机图像分析系统对6例意外死亡尸体标本的完整肩袖及关节囊中神经感觉小体的分布进行研究。结果光镜下在肩袖三层中以及在肩关节囊上可清楚地辨别Pacini小体、Ruffini小体和Golgi腱器官三种力学感受器的形态。这些感受器主要集中分布在肩胛下肌、冈上肌和前方关节囊,以Pacini和Ruffini小体多见。免疫组化染色及图像分析计算结果显示神经末梢分布在组织的表层,但更多的各类粗细神经纤维分布在组织的深层。肩胛下肌、冈上肌和前方关节囊中的神经末梢数量多且直径较粗,而后方关节囊和冈下肌,小圆肌中的神经末梢数量少且直径较细。结论在肩关节囊和肩袖组织中富含三种神经感觉小体,主要集中分布在肩关节前方关节囊、肩胛下肌和冈上肌,且神经纤维较粗。这种分布特征表明神经分布的解剖学特征是保证肩关节正常活动和受外力作用时能够瞬间产生保护性反射而不致损伤的重要因素。

Objective The articular neurohistology is a new approach to explore stabilized and chronic pain mechanisms for joint research. Furthermore, the distribution of mechanoreceptors and their functional condition play an important role in the movement and stability of joint. The animal experimental study suggest that there is a various characteristics of the type and amount of mechanoreceptors in different joints. Pacini corpuscle, Ruffini corpuscle and Golgi tendon organs as joint mechanoreceptors are widely distributed on nearly all of human joint, and have impact on stabilization of joint. The present investigates the neurohistological features of Pacini corpuscle, Ruffini corpuscle and Golgi tendon organs in the rotator cuff and the capsule, and explores their behaviors for maintaining stability of the shoulder joint. Methods Six rotator cuffs and capsules of shoulder joint were obtained from cadavers died of the accident. The tendinous tissue of subscapularis, supraspinatus、infraspinatus, and teres minis were resected from the interface of tendon and muscle to great and lesser tuberosity of humerus, the capsule tissues of glenohumeral were harvested as well. Then, the tissues were cut into a small fragments fixed with the formalin buffer solution, and embed in paraffin. The section was made along the longitudinal axis of the tendon at 150 μm interval with Leitz 1516 machine. The modified Bielschowsky staining and the S-100 immuohistochemical staining were adopted to observe the mechanoreceptors of Pacini corpuscle, Ruffini corpuscle and Golgi tendon organs. The distribution density and size of the sensitive nerve endings were analyzed with Leica imaging process system. Results The tendinous part of rotator cuff could be divided into three layers: synovial, intermediate and articular layer. The morphology of the these three types of mechanoreceptors, Pacini corpuscle, Ruffini corpuscle and Golgi tendon organs, could be identified clearly in the every layer of the tendious tissues under microscopic examination. Pacini corpuscle was ellipse and had multi layer capsule with the thickness of 20-40 μm; Ruffini corpuscle was columnar and 350-550 μm in size; Most of Golgi tendon organs were found at the interface of tendon and muscle. Among of them, the Pacini corpuscle and Ruffini corpuscle were much more than the Golgi tendon organs in rotator cuff and capsule of shoulder. The results of immuohistochemical staining and the counting of nerve ending assisted by the computer showed the number of sensory nerve endings in the subscapularis, supraspinatus and anterior capsule of the shoulder were much more than in the infraspinatus, teres minis and posterior capsule. The diameter of nerve bundle in the subscapularis, supraspinatus and anterior capsule was thicker than in the other periarticular structures. In periarticular structures, the mean value of nerve fiber counting were 25 in infraspinatus, 25 in supraspinatus, 13 in subscapularis, 10 in teres minis, 22 in anterior capsule and 12 in posterior capsule. Conclusion Shoulder capsule and rotator cuff are rich in the three type of mechanoreceptors, Pacini corpuscle, Ruffini corpuscle and Golgi tendon organs. However, there are a different distribution density and size of them in rotator cuff and capsule of shoulder, but the three of mechanoreceptors are mainly concentrated in the subscapularis, supraspinatus and the anterior capsule. S-100 immuohistochemical staining is much more sensitive than the modified Bielschowsky silver staining in displaying the innervations of the rotator cuff and capsule. The characters of the sensory nerve ending distribution in shoulder imply that the innervations of the shoulder play an important role in keeping the stability and mobility of the shoulder.