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pl. bursae,bursas [L.] a small fluid-filled sac or saclike cavity situated in places in tissues where friction would otherwise occur.
Bursae function to facilitate the gliding of skin, 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. See also bursal.
lies between the ligamentum nuchae and the dorsal arch of the atlas. Called also cranial nuchal subligamental bursa.
under the ligamentum nuchae and over the axis. Called also the caudal nuchal subligamental bursa.
intertuberal bursa. See bicipital bursa.
large bursa on the summit of the calcaneus where the superficial digital flexor muscle tendon is partly inserted as it passes distally to the foot; in the horse there may be an additional small subcutaneous bursa over the tendon at this site; its inflammation causes 'capped hock'.
bursa of Fabricius.
embraces the female nematode during copulation; the structure is useful for the identification of some species of nematodes.
cranial nuchal subligamental bursa
see nuchal bursa (below).
see B lymphocyte.
bursa equivalent tissue
an unidentified component of the lymphoid system, analogous to the bursa of Fabricius in birds, which is considered to be the primary site of the origin of B lymphocytes.
bursa of Fabricius
an epithelial outgrowth of the cloaca in birds, which develops in a manner similar to that of the thymus, 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 or antibody immunity.
May be very large in young chickens and compress the cloaca dorsally. It opens into the proctodeum, the most caudal of the three chambers of the cloaca.
a small, serous membrane lined pouch ventral to the aorta and to the right of the esophagus and within the caudal mediastinum.
a bursa beneath the superficial tendon of the infraspinatus muscle as it crosses the greater tubercle of the humerus.
lies between the tendon of the biceps brachialis muscle and the brachial groove of the humerus. Called also bicipital bursa.
a bursa over the intertubercular groove of the humerus and beneath the tendon of the biceps brachii muscle, in horses and cattle.
bursa mucosa, synovial bursa
a closed synovial sac interposed between surfaces that glide upon each other; it may be subcutaneous, submuscular, subfascial or subtendinous in location.
lies between the navicular bone and the deep digital flexor muscle. Called also bursa podotrochlearis manus/pes.
a bursa above the dorsal arch of the atlas and beneath the funicular part of the ligamentum nuchae.
the potential cavity contained within the greater omentum. It communicates with the rest of the peritoneal cavity through the epiploic foramen (of Winslow).
see ovarian bursa.
bursa podotrochlearis manus
see navicular bursa (above).
bursae which develop in subcutaneous sites over any bony prominence, e.g. coxal tuber, olecranon.
between the funicular and lamellar parts of the ligamentum nuchae and over the spine of the second thoracic vertebra of horses.
see bursa mucosa (above).
the space between the body of the epididymis and the testis created by the partly free body of the epididymis relative to its close attachment to the testis.
beneath the tendon of the triceps brachii muscle as it passes over the summit of the olecranon. Called also tricipital bursa.
see triceps bursa (above).
over the greater trochanter between the tendon of the accessory gluteal muscle and the trochanteric cartilage.