What is Shoulder Impingement?

Now that spring is upon us, you may hear the term “shoulder impingement” more often. It is commonly seen in athletes who participate in overhead sports such as softball, baseball, tennis, swimming, and volleyball but can occur in those who perform repetitive overhead activities at work or home as well. The term “impingement” refers to a pinching of soft tissue structures such as tendons and bursa between the shoulder blade (scapula) and the upper arm bone (humerus). This mechanical compression can occur due to rotator cuff weakness or injury, a structural abnormality such as a curved acromion, or an imbalance in the flexibility or strength of the shoulder muscles. The rotator cuff consists of four muscles surrounding the scapula that attach to the humeral head and pull the head down into the socket to allow the arm to move unimpeded during overhead motion. When the rotator cuff is not functioning properly, the humeral head glides instead of rolls upward, pinching the soft structures between it and the acromion (tip of the scapula). With repeated pinching, the bursa and tendons become irritated and inflamed creating bursitis and tendonitis. Symptoms include pain when raising the arm out to the side then overhead, pain can occur during midrange and is known as a painful arc. Pain is usually located at the top of the shoulder but can radiate down the upper arm to the elbow and is worse when reaching overhead, behind the back or when reaching out to the side as when reaching into the back seat while sitting in the front seat. Pain is usually worse during movement and better at rest but may hurt when lying on it at night. When left untreated, the condition may deteriorate and result in a more serious rotator cuff injury. Consult with your physician regarding a diagnosis as treatment may consist of rest from the aggravating factors, injections to reduce inflammation, taping to reduce pain and promote healing, or physical therapy to restore normal shoulder mechanics.