Educational Feature: Common Shoulder Injuries

Common shoulder injuries typically involve the muscles, ligaments and tendons – and rarely, fractured bones.

Repetitive, stressful sport activities as tennis, pitching, or weightlifting can weaken the shoulder and injure the ligaments.

Intensive training routines, involving excessive, repetitive overhead motion of the arm and shoulder, can over time cause shoulder instability and impingement, and a great deal of pain.

  • Shoulder Instability is caused by injured shoulder ligaments allowing the shoulder joint to move out of its normal position. This condition can lead to dislocation of the shoulder joint.
  • Shoulder Impingement is caused by the overuse or abrasion of shoulder muscles on the shoulder blade. This occurs when the arm is lifted away from the body, putting pressure on the rotator cuff soft tissues.

These problems of instability and impingement of the soft tissue or bony structures of the shoulder most often result in weakness in the arm, a limited ability for joint motion and temporary or continuous pain – eventually requiring medical treatment. Ignoring or underestimating the pain and weakness of a shoulder injury may lead to continued aggravation of the condition, potentially causing additional problems.

Loose or torn ligaments, tendons, and shoulder muscles may lead to a constant state of instability and recurring dislocations.
Continuous, severe impingement of the rotator cuff tendons, bursa and muscles can lead to tendinitis and bursitis, and even a rotator cuff tear – all causing pain and restricted movements.

Bursitis is caused by swollen bursae – which are thin, jelly-like sacs that create a cushion between the bones and soft tissues. Bursae usually contain a small amount of lubricating fluid that helps reduce friction between the gliding muscles and the underlying bone. The shoulder bursa is located between the rotator cuff and the shoulder blade. Swelling of the shoulder bursa may be a result of excessive use of the shoulder, causing pain and restriction of movements. Shoulder bursitis often occurs together with rotator cuff tendinitis.

Tendinitis causes swelling of the tendons – which are cords that connect muscle to bone. In the shoulder, there are four rotator cuff tendons and one bicep tendon. Most forms of tendinitis develop over time, due to long-term overuse wearing down the tendon. At first the tendon becomes swollen, causing pain and tenderness in the shoulder. As the tendonitis develops, the tendon may thicken or grow larger, and pain may radiate towards the upper arm. Acute tendinitis can develop from excessive overhead sport activities as ball pitching or throwing. Chronic tendinitis may develop due to degenerative diseases like arthritis.

Tendon tears. Over time, the stress from repetitive shoulder movements may lead to the development of overuse tendon tears. Tendon tears are caused by a partial or complete split of the tendon into two parts – it’s painful and causes weakness in the upper arm. Tears can occur through an acute injury, degenerative changes due to age, or long-term overuse wearing out the tendons. Complete tendon tears – in which the tendon is pulled from the attachment to the bone – are among the most common rotator cuff and bicep tendon injuries.

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