bursa

[Late Latin, purse, pouch, from Greek, skin, wineskin.]

A simple sac or cavity with smooth walls and containing a clear, slightly sticky fluid interposed between two moving surfaces of the body to reduce friction. Subcutaneous bursae are found where the skin stretches around the greater curvature of a joint, as in the elbow or knee, and considerable chafing may occur; they may be single or multiple sacs. These bursae may enlarge as a result of continuous excessive irritation, as in housemaid's knee or miner's elbow. See also Bursitis.

Synovial bursae are small closed sacs of fibrous tissue continuous with the joint cavity of a diarthrosis. They are lined with a complex membrane that secretes a clear lubricating fluid, serving to reduce friction between the opposing surfaces of the articulation. See also Joint (anatomy).

Bursae may exist in the form of elongated sheaths surrounding tendons or ligaments, where these moving bands are in contact with another structure, such as a bone, muscle, or another tendon or ligament. Tendon sheaths are especially common where tendons bend around the ends of two bones at an articulation. See also Muscular system; Skeletal system.

A fluid-filled sac or cavity that reduces friction between the bones, ligaments, and tendons in the body's joints.

Emanating from or pertaining to bursa.

• infectious b. disease — a disease of 3- to 6-week-old chickens caused by an Avibirnavirus which primarily and selectively destroys B lymphocytes in the bursa of Fabricius resulting in a secondary immunodeficiency. Clinical signs are variable and include diarrhea, feather ruffling and droopiness. Death is often a consequence of septicemia associated with normally nonpathogenic strains of bacteria such as Escherichia coli or Salmonella spp. The morbidity in an initial outbreak will be 100% and the mortality up to 30%. Called also Gumboro disease, infectious avian nephrosis.

Bursa may refer to:

• Bursa (formerly known as 'Brusa' and 'Prusa'), the capital of Bursa Province, Turkey
  • Bursa Province, Turkey
  • the Bursa meteorite of 1946, which fell in Bursa, Turkey (see Meteorite falls)
• Bursa (pigeon), a breed of domestic pigeon
• Bursa (anatomy), fluid filled sac located between a bone and tendon
• Bursa Malaysia, the Malaysian stock exchange
• Bursa (genus), a genus of gastropods
• Bursa of Fabricius (also known as Bursa fabricii, cloacal bursa), a lymphatic organ in birds
• Bursa, a fictional semi-intelligent quadruped native to the planet Naboo in the Star Wars universe

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