bursitis

Inflammation of a small fluid-filled sac, called a bursa, that is formed round a joint for its protection. It may be caused by infection, injury, repetitive stress, gout, or arthritis or it may arise for no apparent reason. Except in the case of infection, it may be treated by steroid injection.

In bursitis an excess of serous fluid is secreted by the walls of the bursa, which becomes distended and tense. This may follow a blow to the bursa, in which case the swelling is haemorrhagic. Bursitis is not serious and usually responds to aspiration and firm bandaging. Those with bursitis of the knee should either avoid kneeling or wear a kneeling pad. In purulent bursitis the abscess must be drained. Bursitis which becomes infected does not as a rule recur as the cavity of the bursa becomes obliterated by fibrous adhesions. Housemaid's knee is inflammation of a bursa in front of the knee-cap caused by the irritation of kneeling and bending forwards. Clergyman's knee is inflammation just below the knee, arising from recurrent pressure exerted while kneeling with the rest of the body upright.