Bursitis

Alternative names:

infrapatellar bursitis (below kneecap); olecranon bursitis (elbow); retrocalcaneal bursitis (back of heel)

Definition:

An acute or chronic inflammation of the fluid-filled sac beneath the tendons (bursa).

Causes, incidence, and risk factors:

Bursa are fluid-filled cavities located at tissue sites where tendons or muscles pass over bony prominences. Their function is to facilitate movement and reduce friction between moving parts. The cause of bursitis may be chronic overuse, trauma, rheumatoid arthritis, gout, infection, or unknown. Most bursitis occurs in the shoulder, but it may also affect the knee, elbow, Achilles tendon, first metatarsal of the foot (bunion), or other areas. Chronic inflammation can occur with repeated attacks of bursitis or injury.