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Rotator Cuff Injury

In 75% of cases of shoulder pain, the main source is the supraspinatus tendon of the rotator cuff. The supraspinatus muscle, together with the deltoid, raises the arm to initiate abduction. If there is a complete
tear, the athlete cannot hold the arm elevated in the scapular plane between 60° and 120° and has to drop the shoulder. The arm may swing laterally, at which point the deltoid takes over. The weakest point of the supraspinatus tendon is the part which forms the cuff over the joint in the area that is 1 cm (0.4 in) from the attachment of the tendon to the humerus. It is at this point that ruptures most often occur. They may be either partial or total. In the vulnerable area there is a network of capillaries. With increasing age or overuse there is decreased blood flow; this causes typical degenerative changes, including reduced elasticity and increasing weakness. These changes are often apparent in elderly athletes, but may start at the age of
30–35 years. When the arm is abducted to an angle of 60–120° to the body, and during static work in this position, the blood vessels are compressed; this further impairs the blood flow and reduces the tissue
oxygen supply to increase the risk of injury.


Impingement syndrome (which can be primary or secondary to instability), traction overload tendinitis, and trauma can all cause rotator cuff problems.

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