Bursitis is inflammation (swelling) of a bursa. A bursa is a small fluid-filled sac which forms under the skin, usually over the joints and between tendons and bones.
A bursa can become inflamed through injury or repetitive movement. For example, runners and joggers have an increased risk of developing bursitis in their ankles. Less commonly, bursitis can occur as a result of an infection or as a complication of certain conditions, such as rheumatoid arthritis (see Bursitis - causes for more information).
Bursitis causes pain and swelling in the affected body part. The symptoms of bursitis usually improve within a few weeks. Resting the affected body part and taking painkillers, such as ibuprofen, can help to relieve symptoms and speed up recovery.
There are around 160 bursae in the human body. They can be found in any area where friction occurs.
Bursae act as cushions between two surfaces that rub against each other, such as bones, muscles, joints and tendons, helping to reduce friction. Bursae reduce friction because they're lined with special cells called synovial cells, which produce a liquid that lubricates the moving parts of the body.
Where bursitis occurs
It's possible for any bursa to become inflamed, but the most common places where bursitis occurs are the:
The risk of developing bursitis is increased if you regularly do an activity that involves a lot of repetitive movement. For example, darts players who repeatedly bend and straighten their elbow may get bursitis of the elbow. People who do a lot of kneeling, such as carpet fitters and gardeners, have a high risk of developing bursitis in their knee (known as 'housemaid's knee').
Taking precautions, such as wearing knee pads or warming up before exercise, may help to reduce your risk of getting bursitis. See Bursitis - prevention for more information.
When to see your GP
You should visit your GP if there's no improvement in your symptoms after two weeks.