What is Shoulder Impingement Syndrome?
Shoulder Impingement occurs when there is compression of the shoulder structure which may be caused by muscles that are chronically too tight. Because the muscles are tight, the arm cannot move freely because the surrounding structures are pulled too closely together. This causes compression, grinding, extra friction, and various other strains to various tissues like connective tissue and bursa.
The rotator cuff is a common source of pain in the shoulder. Pain can be the result of:
- Tendinitis: The rotator cuff tendons can be irritated or damaged.
- Bursitis: The bursa can become inflamed and swell with more fluid causing pain.
- Impingement: When you raise your arm to shoulder height, the space between the acromion and rotator cuff narrows. The acromion can rub against (or "impinge" on) the tendon and the bursa, causing irritation and pain.
Your shoulder is made up of three bones:
- your upper arm bone (humerus),
- your shoulder blade (scapula),
- your collarbone (clavicle).
Your arm is kept in your shoulder socket by your rotator cuff. These muscles and tendons form a covering around the head of your upper arm bone and attach it to your shoulder blade. These muscles are the supraspinatus, infraspinatus, subscapu laris, and teres minor.
There is a lubricating sac called a bursa between the rotator cuff and the bone on top of your shoulder (acromion).The bursa allows the rotator cuff tendons to glide freely when you move your arm.
Causes and Risk Factors
Shoulder impingement is most common in:
- Young athletes
- Athletes who regularly use repetitive shoulder motions, like baseball pitchers, tennis players, and swimmers, are at higher risk of developing impingement.
- Middle-aged individuals
- Workers whose jobs involve repetitive lifting or overhead activities, like painters, carpenters, or electricians, are also more likely to develop shoulder impingement.
- There are also intrinsic factors that place individuals at greater risk for shoulder impingement:
- The shape of the acromion
- Bone spurs
- Degenerative changes that occur in some individuals with aging
- Poor posture
- Weak or imbalanced shoulder muscles
Rotator cuff pain commonly causes local swelling and tenderness in the front of the shoulder. You may have pain and stiffness when you lift your arm. There may also be pain when the arm is lowered from an elevated position.
Early symptoms may include:
- Minor pain that is present both with activity and at rest
- Pain radiating from the front of the shoulder to the side of the arm
- Sudden pain with lifting and reaching movements
- Athletes in overhead sports may have pain when throwing or serving a tennis ball
Progresses symptoms may include:
- Pain at night
- Loss of strength and motion
- Difficulty doing activities that place the arm behind the back, such as buttoning or zippering
The diagnosis of bursitis or tendonitis caused by impingement is usually made on the basis of your medical history and physical examination. Your Physical Therapist will ask you detailed questions about your activities and your job , because impingement is frequently related to repeated overhead activities. A doctor may request further imaging studies, such as X-rays to look for bone spurs on the acromion, or an MRI, to look for rotator cuff degeneration or tearing.
Initial treatment for shoulder impingement syndrome is always non-surgical. Rest and avoidance of overhead activities are very helpful in the early stages. A doctor might also recommend oral anti-inflammatory medications, such as aspirin or ibuprofen, or corticosteroid injection. More severe cases of impingement syndrome that have failed to respond to conservative treatment are referred to an orthopedic physician to consider the need for surgical intervention.
Physical therapy care is very helpful in treatment of shoulder impingement syndrome, particularly in the early stages. Research shows that individuals who receive active physical therapy experience greater improvement in function and decreased pain intensity, compared to those performing an exercise program alone.
Physical therapy treatment combines exercises to strengthen the rotator cuff, as well as other muscles which stabilize the shoulder and address any limitations in range of motion. In addition, modalities address pain and inflammation and often manual therapy is indicated to assist in the restoration of shoulder mobility and decreasing soft tissue restrictions. Finally, your Physical Therapist will help guide your return to full function with your arm, as quickly and safely as possible.