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bursa[bur´sah] (pl. bur´sae) (L.)
a small fluid-filled sac or saclike cavity situated in places in tissues where friction would otherwise occur. adj., adj bur´sal. Bursae function to facilitate the gliding of muscles or tendons over bony or ligamentous surfaces. They are numerous and are found throughout the body; the most important are located at the shoulder, elbow, knee, and hip. Inflammation of a bursa is known as bursitis.
bursa of Fabricius an epithelial outgrowth of the cloaca in chick embryos, which develops in a manner similar to that of the thymus in mammals, atrophying after 5 or 6 months and persisting as a fibrous remnant in sexually mature birds. It contains lymphoid follicles, and before involution is a site of formation of B-lymphocytes associated with humoral immunity.
bursa muco´sa (mucous bursa) (synovial bursa) a closed synovial sac interposed between surfaces that glide upon each other; it may be subcutaneous, submuscular, subfascial, or subtendinous in location.
[bur′sə] pl. bursae
Etymology: Gk, byrsa, wineskin
1 a fibrous sac between certain tendons and the bones beneath them. Lined with a synovial membrane that secretes synovial fluid, the bursa acts as a small cushion that allows the tendon to move over the bone as it contracts and relaxes. See also adventitious bursa,bursa of Achilles,olecranon bursa,prepatellar bursa.
Plural of bursa.
A closed sac lined with a synovial membrane and filled with fluid, usually found in areas subject to friction, such as where a tendon passes over a bone.
Mentioned in: Joint Fluid Analysis
n.pl membrane-lined sacs containing synovial fluid, usually found in and around joints. Bursae provide protective cushioning and lubrication.