Impingement / Bursitis

The sub-acromial bursa can get irritated and inflamed for a number of reasons. This includes falling onto your shoulder, instability of your shoulder or shoulder blade that causes movement of the structures around the bursa, or compression of the space between the acromial arch above the bursa and the humeral head below the bursa. There is much discussion in the scientific literature at present as to whether bursitis is actually caused by the impinging of the bursa between the acromial arch and the humeral head, and so the term ‘impingement’ is falling out of favour with some clinicians. It is however as easy way to understand how the bursa can become injured and so may be a useful conceptual idea for bursitis.

Bursitis in your shoulder usually settles down when it is no longer being irritated. It is useful to think of bursitis as the result of other problems in your shoulder, rather than the cause of your problems. Often addressing these problems through strengthening, stretching, or rest can be helpful. These problems that can cause bursitis include:

1. micro shoulder instability

2. decreased shoulder ROM

3. fall directly onto shoulder

4. rotator cuff tear

Steroid injections can be administered to decrease the irritation of your bursa, but without addressing the underlying cause of the bursitis, the bursa can easily become irritated and painful again. Additionally, the administration of steroid can have harmful effects to the other structures around your shoulder and so should only be used if absolutely necessary.

For more information about the anatomy of your shoulder, you can check out this video or the useful website from the University of Otago www.shoulderpain.org.nz