抄録
The subscapularis tendon (SSC) insertion is one of the key structures that stabilizes the LHB. The purpose of this study was to investigate the anatomy of the most superior portion of the SSC insertion and clarify the relation between the SSC insertion and the pathway of the LHB. 20 embalmed shoulder girdles of cadavers were used in this study. After the acromion and the coradoid process were cut off, connective tissues were carefully removed and the SSC insertion was observed. In 4 specimens, muscle fibers of the SSC were carefully removed in water to observe the intramuscular tendons of the subscapularis. The SSC inserted onto the medial portion and the superior surface of the lesser tuberosity. The most proximal insertion of the tendon, derived from the most proximal portion of the intramuscular tendon, formed an anteromedial wall and stabilized the LHB at a more proximal portion continuing from the bicipital groove. Further, the most proximal insertion of the SSC extended superiorly and formed a thin tendinous slip, which attached to the fovea capitis of the humerus. Both of the most proximal insertion of the SSC and the tendinous slip created the semitubular structure and lengthened a channel of the LHB proximally. These results suggested that the most proximal portion of the SSC and the slip can reinforce the channel of the LHB which changes direction from the bicipital groove to the superior tubercle of the glenoid at this portion. Clinically, in shoulders with a SSC injury, repairing the most proximal portion of this tendon was important in terms of the LHB stability.
