Ramsay Générale de Santé, Hôpital Privé Jean Mermoz, Centre Orthopédique Santy, Lyon, France.
Service d'anatomopathologie, Centre Hospitalier Lyon-Sud, Pierre Bénite, France.
J Shoulder Elbow Surg. 2019 May;28(5):959-965. doi: 10.1016/j.jse.2018.11.045. Epub 2019 Jan 30.
Although subscapularis tendon lesions seem to differ from those of the supraspinatus tendon, the features they have in common suggest that the subscapularis tendon may also have 2 distinct layers. Our aim was therefore to characterize the histologic structure of the subscapularis tendon from its humeral insertion point to the musculotendinous junction.
A histologic study was performed on 10 autopsy samples. The subscapularis tendon was extracted in one piece from the musculotendinous junction to the humeral insertion point and was prepared using standard (hematoxylin-eosin-saffron) staining.
Histologic analysis revealed 2 fibrous layers, distinguishable by the orientation of the collagen bundles. The deep layer was thinner and composed of parallel longitudinal collagen fibers inserting onto the lesser tuberosity flush with the cartilage. The superficial layer was thicker and composed of interdigitated collagen bundles inserting onto the lesser and the greater tuberosity after splitting into 2 bands, 1 lining the floor of the bicipital groove, and the other extending over the long head of the biceps tendon across the groove. Each layer formed an independent musculotendinous junction in the subscapularis muscle.
The subscapularis tendon is composed of 2 distinct fibrous layers, just like the supraspinatus tendon, but arranged differently. The superficial layer of the subscapularis tendon passes across the bicipital groove and forms a fibrous ring around the long head of the biceps tendon that stabilizes the latter in the bicipital groove. These results explain some of the specific features of subscapularis tears described in the literature, namely, delamination and biceps subluxation.
虽然肩胛下肌腱病变似乎与冈上肌腱病变不同，但它们的共同特征表明肩胛下肌腱也可能有 2 个不同的层面。因此，我们的目的是从肩胛下肌腱的肱骨附着点到肌腱肌腹连接部来描述其组织学结构。
对 10 例尸检标本进行了组织学研究。肩胛下肌腱从肌腱肌腹连接部整块提取到肱骨附着点，并使用标准（苏木精-伊红-番红）染色进行制备。
组织学分析显示有 2 个纤维层，可通过胶原束的方向来区分。深层较薄，由平行的纵向胶原纤维插入小结节，与软骨平齐。浅层较厚，由交错的胶原束插入小结节和大结节，然后分成 2 束，1 束沿二头肌沟的底部排列，另 1 束延伸越过二头肌长头肌腱跨越沟。每个层在肩胛下肌中形成一个独立的肌腱肌腹连接部。
肩胛下肌腱由 2 个不同的纤维层组成，就像冈上肌腱一样，但排列方式不同。肩胛下肌腱的浅层穿过二头肌沟并在二头肌长头肌腱周围形成一个纤维环，稳定后者在二头肌沟内。这些结果解释了文献中描述的一些肩胛下肌腱撕裂的特定特征，即分层和二头肌脱位。
