Also found in: Dictionary, Thesaurus, Encyclopedia.


 [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.
subacromial bursa one between the acromion and the insertion of the supraspinatus muscle, extending between the deltoid and the greater tubercle of the humerus. See illustration.
Subacromial bursa, lying between the acromion and supraspinatus tendon and extending between the deltoid and greater tubercle. From Dorland's, 2000.


[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.
2 a sac or closed cavity. See also omental bursa,pharyngeal bursa. bursal, adj.


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

bursae (burˑ·sā),

n.pl membrane-lined sacs containing synovial fluid, usually found in and around joints. Bursae provide protective cushioning and lubrication.
References in periodicals archive ?
A distinguishing factor between CPPD and HA is that HA typically involves tendons, bursae, and periarticular tissue, whereas CPPD typically deposits in hyaline and fibrocartilage.
At Tsaraepae, all five specimens were young birds (with bursae and/or incompletely ossified skulls): two were undergoing wing molt, three were in tail molt, and all were undergoing body molt.
Potential pain generating structures such as the lateral collateral ligament, lateral meniscus, bursae and the joint capsule should also be considered when attempting to palpate the popliteal tendon near its femoral insertion.
Bursitis: A condition involving inflammation of the bursae.
polyobotaria (Oberthur, 1923), but can easily be separated by the following features: 5 transverse fasciae in the forewing, 4 transverse fasciae in the hindwing; 8th segment of abdomen strongly sclerotized, ostium arc-shaped, corpus bursae circular and without filiform structure in female genitalia.
1), (2) Physiological compression occurs during elbow flexion, but compression may also be the result of masses in the tunnel, including ganglions and bursae or synovitis or osteophytes.
12) Deep bursal infection is typically hematogenous, whereas the superficial bursae, such as those overlying the olecranon or patellar tendon, are often infected secondary to penetrating trauma.
DIAGNOSIS: Recognized by the shiny black basic coloration, brown antennal segment I and basal 1/5 of II, dense, silvery, reclining setae on anterior part of the totally blackened scutellum, anteriorly flattened and pruinose procoxa, well developed metafemur, widened posterior wall of bursae, and narrowed sclerotized rings.
Other species, such as the side-necked turtles of Australia, cope by using specialised cavities in their rear, known as cloacal bursae, to draw in water and remove the oxygen.
However, when they do occur, both rapid-and slow-growing species have been implicated in chronic granulomatous infections involving tendon sheaths, bursae, bones, and joints.
They must be differentiated from bursae, especially around the knee, and from lipomas.
It is also true that pharyngeal bursae, which are essentially potential Tornwaldt's cysts, are more detectable at autopsy than on imaging, but there is no suggestion that the authors of the early incidence studies (13,14) confused the two.

Full browser ?