What is sub-acromial impingement?

Sub-acromial impingement refers to a spectrum of symptoms that are caused by compression of bursa or Rotator Cuff tendon between the humeral head (ball of the socket) and the acromion (bony bridge across the top of the joint). This is a diagnosis that refers to the symptoms but does not explain the cause. As a diagnosis this is of limited use in informing management unless the underlying causes of this impingement are identified.

If you have symptoms of shoulder impingement it is important to understand why these have occurred. Sometimes there is a structural reason (such as shape of acromion or bony spur) but often the main cause is ‘functional’. This means that structures are not unusual but your sub-acromial space is being reduced by the way the scapula and humeral head is being controlled. Physiotherapy plays an important role in identifying and addressing the sometime subtle postural, muscular and joint problems that cause functional sub-acromial impingement.

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