A bursa is rather like a small flattened balloon containing fluid. There are many bursae in the body and they are usually found between a bony surface and the overlying muscles or tendons or superficially over hard bony prominences. Their role is to provide protection, as under the skin over the knee cap (pre-patellar bursa) for example and lubrication, as with the subacromial bursa under the shoulder where as well as protecting the underlying tendons the bursa promotes freer gliding of the joint.
The bursa may become inflamed when it is a bursitis. A bursitis is usually associated with swelling and tenderness and pain on certain movements. Examples are ‘housemaid’s knee’ (pre-patellar bursitis) and trochanteric bursitis where the pain is felt over the bony point at the top of the outer thigh.
Physiotherapy can help by applying electrotherapy, usually ultrasound, over the bursa and soft tissue massage can also help the swelling to disperse. If it doesn’t respond quickly it may need to be drained of its fluid by your GP who may also inject it with steroid or prescribe an anti-inflammatory tablet (NSAID – non-steroidal anti-inflammatory drug).