Bursa or bursae (plural) are fluid-filled sacs that are present around joints. They provide cushioning effect to the bones when skin, muscles, or tendons rub against them. Bursae play an important role in providing protection against friction during movement. In case of any disorder of the bursae, movement becomes difficult and painful. Bursae are present all over the body wherever tendons move across bones. While there are around 160 bursae at birth, new ones may form as a result of friction. IN case of people who wear shoes or for someone who has an abnormal foot anatomy, an abnormal bursa might develop in the big toe joint (See: Bunion). Being lubricated fluid-containing sacs, they are present a bone and any opposing surface. Bursae occur in various sizes, but the healthy ones are generally thin. Bursae contain synovial fluid in a synovial membrane. The synovial fluid is itself a viscous fluid and looks like the white of an egg. The viscous nature gives protection against friction. Bursae are of three types – synovial, subcutaneous, and adventitious. Adventitious bursae form with repeated shearing stress on the soft tissue. Subcutaneous bursae form when sheets of fibrous tissue form at the junction of the subcutaneous tissue. Some common conditions of bursae include bursitis (inflammation of the bursae), which is a result of mechanical friction, infectious bursal disease, formation of cysts, tendinitis, and musculoskeletal connective tissue diseases. Diseases of the bursae are diagnosed by an ultrasound, MRI, and in some cases, aspiration. Treatment for bursal diseases include taking rest, prescription of NSAIDs, corticosteroid injections, and treatment for infections, if present. Since bursitis can occur in any of the joints where there is friction, people with diabetes are prone to bursitis. Bursitis generally occurs in the shoulder, elbow, knee, hips, ankle, thigh, and buttocks. Since diabetes and high blood sugar levels act on the immune system and the blood vessels, people with diabetes are prone to get septic bursitis. Reduced blood supply to the tendons and the thickening of tendons in people with diabetes creates susceptibility to tendinitis and bursitis.