Tendons are cord-like bands of tissue that connect muscles to bone and tendon tissue is made of a tough, fibrous substance called collagen that can withstand quite a bit of force and tension. Overtime, tendons can become inflamed and painful and tendon injuries can result in the shoulder joint as well as in the elbow, knee and ankle.
Doctors may use different terms to describe a tendon injury including tendinitis, tendinosis or tendinopathy. Many common sports afflictions, including tennis elbow, golfer’s elbow, swimmer's shoulder, and jumper's knee are actually forms of tendinitis/tendinosis.
Your arm is kept in your shoulder socket by your rotator cuff, a collection of muscles and tendons that stabilize the shoulder. The rotator cuff is comprised of four tendons and muscles that originate from the “wing bone” or the shoulder blade and together they combine to form a cuff over the upper end of the arm, the head of the upper arm bone or humerus.
The rotator cuff helps to lift and rotate the arm and to stabilize the ball of the shoulder within the joint. Rotator cuff tendinitis is irritation or inflammation of the tendons and muscles that help move your shoulder joint. It is also called shoulder impingement.
Shoulder tendinitis or impingement occurs when the tendons of the rotator cuff and the bursae, the fluid-filled sacs that cushion them, are pinched in the narrow space beneath the bony edge of the shoulder blade. Rotator cuff tendinitis can develop over time as the result of a minor injury, or as a result of repetitive motions that lead to inflammation in the bursae.
It is a common injury in athletes who use overhead throwing or lifting motions, young athletes who use their arms overhead for swimming, baseball, and tennis and those who do repetitive lifting or overhead activities using the arm, such as paper hanging, construction, or painting.
Tendinitis causes pain throughout the shoulder joint extending as far as the elbow that may be manageable at first but typically worsens over time. Other symptoms include decreased range of motion and strength in the shoulder; after a prolonged period, it may be difficult to lift the arm over the head. Usually symptoms appear after a period of overuse of the shoulder joint, with increased pain described as a constant tooth ache that radiates down the front of the arm. The pinching may become worse when the arm is raised away from the side of the body.
Treatment is often nonsurgical, with medications to reduce inflammation and physical therapy. If the shoulder does not improve with these treatments, surgery may be required.