Shoulder impingement is a common cause of shoulder pain, where a tendon inside the shoulder rubs or catches on nearby tissue and bone as you lift your arm. It affects the rotator cuff tendon, which is the rubbery tissue that connects the muscles around your shoulder joint to the top of your arm. Shoulder impingement can start suddenly or come on gradually, and symptoms include pain in the top and outer side of your shoulder, difficulty lifting your arm, and weakness in the affected arm.

Shoulder impingement syndrome is the result of a vicious cycle of rubbing of the rotator cuff between your humerus and top outer edge of your shoulder. The rubbing leads to more swelling and further narrowing of the space, which results in pain and irritation. Shoulder impingement can also result from an injury, such as a fall onto an outstretched arm or directly onto the shoulder.

Shoulder impingement is closely related to other common sources of pain in the shoulder called bursitis and rotator cuff tendonitis. These conditions can occur alone or in combination. Physical therapy is a common treatment for shoulder impingement, and a physical therapist will initially focus on restoring normal motion to your shoulder. Stretching exercises to improve range of motion are very helpful. Steroid injections and surgery may also be used to treat shoulder impingement.