Causes and Symptoms of Subacromial Impingement

The rotator cuff is made up of four muscles and the tendons attached to them under the shoulder roof that lowers and raise the arm. Acromion is an extension of the shoulder blade. Subacromial bursa lies in the space between the acromion and the rotator cuff. Subacromial bursa is a sac filled with fluid that allows the rotator cuff beneath the acromion to glide smoothly when the shoulder is moved.

If the four tendons in the rotator cuff are injured, strained or a bone spur develops on the acromion, it can result in the swelling of tendons and also in the rubbing or pinching against the acromion as space between the tendons and acromion gets narrowed. The tendons get irritated when they pass through this acromial space. This is called subacromial impingement.

Subacromial impingement is also known as shoulder impingement syndrome, supraspinatus syndrome, painful arc syndrome, thrower's shoulder and swimmer's shoulder.
Repeated activity where the shoulders are moved overhead like in tennis, painting, swimming, lifting and abnormalities in bones and joints are the risk factors of subacromial impingement.

Causes:
The exact cause of impingement is not explicitly known.

1. Tendon may split if there is continuous wear and tear
2. It may be caused by minor injuries. However, this injury may be triggered by repeated overhead activities as well.
3. Age is another cause. As one grows older, bone spurs may develop on the acromion. Also the tendons are prone to tearing after the age of 40.
4. Sometimes the acromion shape can make people prone to subacromial impingement.

Symptoms:
Subacromial impingement presents itself with the following symptoms:

1. Reaching above behind your back and reaching overhead with your arms gets difficult.
2. Shoulder muscles weaken
3. The tendons can actually tear in two if injuries persist for a considerable duration. This can result in rotator tear cuff. Elevating your arms gets very difficult.
4. Bicep tears are common if impingement persists.