Shoulder Impingement
Posted on Wed, Dec 22, 2010 @ 01:15 PM
The shoulder is one of the most complex and mobile joints in the human body. The shoulder allows us to control where we can move our arms in order to use them for important daily tasks such as reaching, lifting and dressing as well as more complex tasks such as throwing and catching a ball.
The shoulder is made up of three bones: the scapula, the humerus and the clavicle, as well as a network of muscles and ligaments to help move and control the positioning of the arm and hand in space. These bones and muscles need to all work together as a unit in order to provide accurate and concise movements. When there is a dysfunction within these joints due to decreased strength, bony abnormality or trauma, pain can arise.
Impingement is one of the most frequently diagnosed and treated conditions in the shoulder. It can most commonly result from pressure on the rotator cuff from part of the shoulder blade (scapula) as the arm is lifted. The rotator cuff muscles and tendons pass through a narrow space between the scapula’s acromion and humerus at the top of the shoulder. Usually there is enough space in order for these tendons to slide under the acromian as the arm is raised. If there is further narrowing of this space occurring from osteoarthritic changes, inflammation of bursa, acromion shape, thickening of surrounding ligaments or loss of muscle function then impingement can occur.
Impingement Syndrome can be classified as External or Internal:
External Impingement can be either primary or secondary. Primary is usually due to bony abnormalities in the shape of the acromial arch, congenital abnormalities or degenerative changes such as bony spurs which may form under arch. Secondary is usually due to muscular imbalances and/or poor scapular and rotator cuff muscular strength and stabilization which alters the physical position of the acromion, thus causing the tendons to become impinged.
Internal impingement occurs predominantly in athletes where throwing is the main part of the sport. This occurs when the rotator cuff tendons are impinged against the labrum (a fibrous ring of tissue which attaches to a shallow depression of the scapula where the ball of the humerus sits) thus causing pain in the front and/or back of the shoulder.
Impingement typically occurs to some degree each day in everyone’s shoulder during daily activities when the arm is raised above shoulder level. This motion does not necessarily lead to prolonged pain. Continuously working overhead or repeated activities such as throwing can lead to swelling or damage to the bursa or rotator cuff tendons causing pain and irritation.
Typical signs and symptoms of impingement syndrome are weakness, loss of movement and pain when raising the arm to the front or side, typically above 90 degrees. The pain can worsen during overhead motions or during sleep while rolling onto the affected shoulder. Additionally, a sharp pain when reaching into your back pocket can indicate signs of impingement syndrome. As the condition worsens the discomfort will increase subsequently leading to further stiffness, pain, catching, clicking, weakness and potential tearing of the rotator cuff muscles. Inability to raise the arm to the side without assistance may indicate that the rotator cuff tendons are actually torn.
A diagnosis of impingement is made on the basis of medical history, physical examination and diagnostic imaging. An x-ray and MRI are the most common forms of imaging used. An x-ray will help look for an abnormal acromian or bone spurs. An MRI may be performed if a rotator cuff tear is suspected.
Treatment typically consists of physical therapy in conjunction with ice and anti-inflammatory medicine. Physical therapy can consist of modalities to help with pain and swelling, hands on treatments of stretching, joint mobilizations and resistance exercises to help restore range of motion and strength. Improving strength and motion of the rotator cuff and scapular musculature will assist the humerus to move in the socket without pinching the tendons or bursa under the acromion.
In a recent study, 89% of those individuals having impingement syndrome without rotator cuff tears treated conservatively saw improvements in strength, range of motion, pain and were able to return to prior activities.
If experiencing pain and symptoms similar to those described above, have a discussion with your doctor or physical therapist to discuss your options and devise the most appropriate treatment plan for you.
--LaChance