棘上筋 （きょくじょうきん、英：supraspinatus muscle）筋
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・ 背部からみると羽根状の扁平のような筋に見えるが、筋腹は厚く、中央には腱が上腕骨頭へと走っている。
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三角筋の補助的に上腕骨を外転させている。
・ 神 経 ： 肩甲上神経 ※ 資料により違いが見られる。
1. Ｃ5 2. Ｃ5, Ｃ6 3. Ｃ4～Ｃ6
・ 脈 管 ： 肩甲上動脈
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The supraspinatus (plural supraspinati) is a relatively small muscle of the upper back that runs from the supraspinous fossa superior portion of the scapula (shoulder blade) to the greater tubercle of the humerus. It is one of the four rotator cuff muscles and also abducts the arm at the shoulder. The spine of the scapula separates the supraspinatus muscle from the infraspinatus muscle, which originates below the spine.
【Structure】
The supraspinatus muscle arises from the supraspinous fossa, a shallow depression in the body of the scapula above its spine. The supraspinatus muscle tendon passes laterally beneath the cover of the acromion. Research in 1996 showed that the postero-lateral origin was more lateral than classically described.
The supraspinatus tendon is inserted into the superior facet of the greater tubercle of the humerus. The distal attachments of the three rotator cuff muscles that insert into the greater tubercle of the humerus can be abbreviated as SIT when viewed from superior to inferior (for supraspinatus, infraspinatus, and teres minor), or SITS when the subscapularis muscle, which attaches to the lesser tubercle of the humerus, is included.
【 Nerve supply 】
The suprascapular nerve (C5) innervates the supraspinatus muscle as well as the infraspinatus muscle. It comes from the upper trunk of the brachial plexus. This nerve can be damaged along its course in fractures of the overlying clavicle, which can reduce the person's ability to initiate the abduction.
【 Function 】
The supraspinatus muscle performs abduction of the arm, and pulls the head of the humerus medially towards the glenoid cavity. It independently prevents the head of the humerus to slip inferiorly. The supraspinatus works in cooperation with the deltoid muscle to perform abduction, including when the arm is in adducted position. Beyond 15 degrees the deltoid muscle becomes increasingly more effective at abducting the arm and becomes the main propagator of this action.[6]
【 語 句 】
・ supraspinous fossa ： 棘上窩 ・ scapula ： 肩甲骨 ・ greater tubercle ： 大結節 ・ humerus ： 上腕骨 ・ rotator cuff ： ローテーターカフ/回旋筋腱板 ・ abduct ： 外転する ・ spine of the scapula ： 肩甲棘 ・ infraspinatus muscle ： 棘下筋 ・ acromion ： 肩峰 ・ abbreviate ： 短縮する ・ distal ： 末端の ・ teres minor ： 小円筋 ・ lesser tubercle ： 小結節 ・ suprascapular nerve ： 肩甲上神経 ・ brachial plexus ： 腕神経叢 ・ fracture ： 骨折 ・ clavicle ： 鎖骨 ・ initiate ： 始める ・ glenoid cavity ： 関節窩 ・ deltoid muscle ： 三角筋 ・ propagator ： 繁殖者/宣伝者
