The four muscles that raise and lower the arm (and their respective tendons) are collectively known as the rotator cuff. This group of tissues fits neatly under the roof of the shoulder (an extension of the shoulder blade known as the acromion).

If the cuff becomes inflamed, or some bone deformity (usually a bone spur) exists in the acromion, the rotator cuff and acromion can rub against one another, causing a painful condition known as impingement.

Each time the arm is raised there is a bit of rubbing on the tendons and the bursa (small fluid-filled sacs located in the shoulder to lubricate the joint and reduce friction) between the tendons and the acromion, which may cause pain and inflammation.

Almost everyone will experience some degree of impingement due to the daily activities performed with the arm above shoulder level. Impingement may become a serious problem for some people and disturb normal activities. This is when treatment is needed. The impingement process may get worse if any condition decreases the amount of space between the acromion and the rotator cuff tendons or if bone spurs are present.


The underlying causes of subacromial impingement syndrome are multifactorial, but rotator cuff dysfunction (weakness) is probably the most likely cause. In a normal shoulder, the co-ordinated action of the rotator cuff muscles stops any abnormal contact within the subacromial space between the opposing bony surfaces.

Rotator cuff dysfunction is often due to degenerative changes within the rotator cuff muscles and is an age related phenomenon (>40 years). In a minority of cases, rotator cuff dysfunction may follow a painful injury or traumatic tear of the rotator cuff muscles.


  • Avoid excessive overhead activities.
  • Strengthen your shoulders and do not try to play or work through the pain.
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