Medical Dictionary banner
Medical Dictionary - Dictionary of Medicine and Human Biology

Medical Dictionary


bulb (bulb) [TA]
1. Any globular or fusiform structure. SYN: bulbus [TA] . 2. A short, vertical underground stem of plants, such as onion and garlic. [L. bulbus, a bulbous root] aortic b. [TA] the dilated first part of the aorta containing the aortic semilunar valves and the aortic sinuses. SYN: arterial b., bulbus aortae. arterial b. SYN: aortic b.. Braasch b. SYN: Braasch catheter. carotid b. SYN: carotid sinus. b. of corpus spongiosum SYN: b. of penis. dental b. the papilla, derived from mesoderm, that forms the part of the primordium of a tooth that is situated within the cup-shaped enamel organ. duodenal b. SYN: duodenal cap. end b. one of the oval or rounded bodies in which the sensory nerve fibers terminate in mucous membrane. b. of eye SYN: eyeball. hair b. SYN: b. of hair. b. of hair hair b., the lower expanded extremity of the hair follicle that fits like a cap over the papilla pili. SYN: bulbus pili, hair b.. jugular b. SYN: b. of jugular vein. b. of jugular vein [TA] one of two dilated parts of the internal jugular vein: (1) the superior b. (Heister diverticulum) is a dilation at the beginning of the internal jugular vein in the jugular fossa of the temporal bone (bulbus superior venae jugularis [TA]); (2) the inferior b. is a dilated portion of the vein just before it reaches the brachiocephalic vein (bulbus inferior venae jugularis [TA]). SYN: jugular b.. SYN: bulbus venae jugularis [TA] . Krause end bulbs nerve terminals in skin, mouth, conjunctiva, and other parts, consisting of a laminated capsule of connective tissue enclosing the terminal, branched, convoluted ending of an afferent nerve fiber; generally believed to be sensitive to cold. SYN: bulboid corpuscles, corpuscula bulboidea. b. of occipital horn [TA] a rounded elevation in the dorsal part of the medial wall of the posterior horn of the lateral ventricle, produced by the major forceps. SYN: bulbus cornus posterioris [TA] . olfactory b. [TA] the grayish expanded rostral extremity of the olfactory tract, lying on the cribriform plate of the ethmoid and receiving the olfactory filaments. SYN: bulbus olfactorius [TA] . b. of penis [TA] the expanded proximal (posterior) part of the corpus spongiosum of the penis lying in the interval between the crura of the penis and containing the somewhat dilated and angulated portion of the spongy urethra. SYN: bulbus penis [TA] , b. of corpus spongiosum, b. of urethra, bulbus urethrae. b. of posterior horn of lateral ventricle of brain SYN: bulbus cornus posterioris. Rouget b. a venous plexus on the surface of the ovary. speech b. a speech prosthesis used to close a cleft or other opening in the hard or soft palate, or to replace absent tissue necessary for the production of good speech. taste b. SYN: taste bud. b. of urethra SYN: b. of penis. b. of vestibule [TA] a mass of erectile tissue on either side of the vagina united anterior to the urethra by the commissura bulborum. SYN: bulbus vestibuli vaginae [TA] .

bulbar (bul′bar)
1. Relating to a bulb. 2. Relating to the rhombencephalon (hindbrain). 3. Bulb-shaped; resembling a bulb.

bulbi (bul′bi)
Plural of bulbus.

bulbitis (bul-bi′tis)
Inflammation of the bulbous portion of the urethra.

Bulb; bulbus [L. bulbus]

bulbocapnine (bul′bo-kap′nin)
Drug derived from roots of Corydalis cava and C. tuberosa (family Fumariaceae) and Dicentra canadensis (family Papaveraceae); blocks the effects of dopamine on peripheral dopamine receptors.

bulbocavernosus (bul′bo-kav-er-no′sus)
See musculus b..

bulboid (bul′boyd)
Bulb-shaped. [bulbo- + G. eidos, resemblance]

bulbonuclear (bul-bo-noo′kle-ar)
Relating to the nuclei in the medulla oblongata.

bulbopontine (bul-bo-pon′ten)
Relating to the rostral part of the rhombencephalon composed of the pons and overlying tegmentum.

bulbosacral (bul′bo-sa′kral)
See b. system.

bulbospinal (bul-bo-spi′nal)
Relating to the medulla oblongata and spinal cord, particularly to nerve fibers interconnecting the two. SYN: spinobulbar.

bulbourethral (bul′bo-u-re′thral)
Relating to the bulbus penis and the urethra. SYN: urethrobulbar.

bulbus, gen. and pl. bulbi (bul′bus, -bi) [TA]
SYN: bulb (1) . [L. a plant bulb] b. aortae SYN: aortic bulb. b. cordis a transitory dilation in the embryonic heart where the arterial trunk joins the ventral roots of the aortic arches. b. cornus posterioris [TA] SYN: bulb of occipital horn. SYN: bulb of posterior horn of lateral ventricle of brain. b. duodeni ampulla of duodenum. b. oculi [TA] SYN: eyeball. b. olfactorius [TA] SYN: olfactory bulb. b. penis [TA] SYN: bulb of penis. b. pili SYN: bulb of hair. b. urethrae SYN: bulb of penis. b. venae jugularis [TA] SYN: bulb of jugular vein. b. vestibuli vaginae [TA] SYN: bulb of vestibule.

bulesis (boo-le′sis)
The will; a willing. [G. boulesis, a willing]

bulimia (boo-lim′e-a)
SYN: b. nervosa. [G. bous, ox, + limos, hunger] b. nervosa a chronic morbid disorder involving repeated and secretive episodic bouts of eating characterized by uncontrolled rapid ingestion of large quantities of food over a short period of time (binge eating), followed by self-induced vomiting, use of laxatives or diuretics, fasting, or vigorous exercise in order to prevent weight gain; often accompanied by feelings of guilt, depression, or self-disgust. SYN: boulimia, b., hyperorexia.

bulimic (boo-lim′ik)
Relating to, or suffering from, bulimia nervosa.

Bulinus (bu-li′nus)
A genus and subgenus of freshwater snails in the family Planorbidae (subfamily Bulininae), which includes many species that are intermediate hosts of the human blood fluke, Schistosoma haematobium, in Africa and the Middle East; divided into two subgenera, Physopsis and B., the former being responsible for transmission of S. haematobium south of the Sahara, the latter responsible for transmission of this bladder blood fluke in north Africa and the Middle East. Important species include B. truncatus and B. forskalii, hosts for human and animal schistosomes and several domestic animal amphistome flukes.

bulkage (bulk′ij)
Anything, such as agar, that increases the bulk of material in the intestine, thereby stimulating peristalsis.

Abbreviation for L. bulliens, bulliat, or bulliant, boiling, let boil.

bulla, gen. and pl. bullae (bul′a, -e)
1. A fluid-filled blister greater than 100 cm in diameter appearing as a circumscribed area of separation of the epidermis from the subepidermal structure (subepidermal b.) or as a circumscribed area of separation of epidermal cells (intraepidermal b.) caused by the presence of serum, or occasionally by an injected substance. 2. [NA] A bubblelike structure. [L. bubble] ethmoidal b. [TA] a bulging of the inner wall of the ethmoidal labyrinth in the middle meatus of the nose, just below the middle nasal concha; it is regarded as a rudimentary concha. SYN: b. ethmoidalis [TA] . b. ethmoidalis [TA] SYN: ethmoidal b.. pulmonary b. air-filled emphysematous space larger than one centimeter, usually located in the lung periphery; can reach large diameter and cause symptoms by compression of normal lung tissue. Cf.:pulmonary bleb.

bullectomy (bul-ek′to-me)
Resection of a bulla; helpful in treating some forms of bullous emphysema, in which giant bullae compress functioning lung tissue.

bullous (bul′us)
Relating to, of the nature of, or marked by, bullae.

bumetanide (bu-met′a-nid)
A diuretic used in the treatment of edema associated with congestive heart failure, hepatic cirrhosis, and renal disease, resembles furosemide.

Oswald C.E., German neurologist, 1877–1950. See B. pupil.

Abbreviation for blood urea nitrogen.

bunamidine hydrochloride (bun-am′i-den)
An anthelmintic.

bundle (bun′dl) [TA]
A structure composed of a group of fibers, muscular or nervous; a fasciculus. SYN: fasciculus (3) [TA] . aberrant bundles a group, or groups, of fibers from the corticobulbar or corticonuclear tract, directed to each of the motor nuclei of cranial nerves. anterior ground b. SYN: fasciculus proprius anterior. See fasciculi proprii, under fasciculus. Arnold b. SYN: temporopontine tract. atrioventricular b. [TA] the b. of modified cardiac muscle fibers that begins at the atrioventricular node as the trunk of the atrioventricular b. and passes through the right atrioventricular fibrous ring to the membranous part of the interventricular septum where the trunk divides into two branches, the right b. (crus dextrum) of the atrioventricular b. and the left b. (crus sinistrum) of the atrioventricular b.; the two crura ramify in the subendocardium of their respective ventricles. SYN: fasciculus atrioventricularis [TA] , atrioventricular band, Gaskell bridge, His band, His b., Keith b., Kent b. (1) , Kent-His b., truncus fascicularis atrioventricularis, trunk of atrioventricular b., ventriculonector. Bachmann b. division of the theoretical anterior internodal tract that continues into the left atrium providing a specialized path for interatrial conduction. The anatomic reality of this structure has been disputed. comma b. of Schultze SYN: semilunar fasciculus. Flechsig ground bundles [TA] fasciculus proprius anterior [TA] and fasciculus proprius lateralis [TA]. See fasciculi proprii, under fasciculus. Gantzer accessory b. Gantzer muscle. Gierke respiratory b. SYN: solitary tract. ground bundles SYN: fasciculi proprii, under fasciculus. Held b. SYN: tectospinal tract. Helie b. a vertically arched b. of fibers in the superficial layer of the myometrium. Helweg b. SYN: olivospinal tract. Helwig b. SYN: olivospinal fibers, under fiber. His b. SYN: atrioventricular b.. Hoche b. semilunar fasciculus. hooked b. of Russell SYN: uncinate fasciculus of cerebellum. Keith b. SYN: atrioventricular b.. Kent b. 1. SYN: atrioventricular b.. 2. a muscle fiber b. in the mammalian heart below the atrioventricular node; may also occur in humans. Kent-His b. SYN: atrioventricular b.. Killian b. inferior constrictor (muscle) of pharynx. Krause respiratory b. SYN: solitary tract. lateral ground b. obsolescent. See fasciculi proprii, under fasciculus. lateral proprius b. SYN: fasciculi proprii, under fasciculus. left b. of atrioventricular b. [TA] the left limb or branch of the atrioventricular b. that separates from the atrioventricular b. just below the membranous portion of the interventricular septum to descend the septal wall of the left ventricle and begins to ramify subendocardially. SYN: crus sinistrum fasciculi atrioventricularis, left crus of atrioventricular b.. Lissauer b. SYN: dorsolateral fasciculus. Loewenthal b. SYN: tectospinal tract. longitudinal pontine bundles SYN: longitudinal pontine fasciculi, under fasciculus. medial forebrain b. [TA] a fiber system coursing longitudinally through the lateral zone (area) of the hypothalamus, connecting the latter reciprocally with the midbrain tegmentum and with various components of the limbic system; it also carries fibers from norepinephrine-containing and serotonin-containing cell groups in the brainstem to the hypothalamus and cerebral cortex, as well as dopamine-carrying fibers from the substantia nigra to the caudate nucleus and putamen. SYN: fasciculus medialis telencephali [TA] . medial longitudinal b. SYN: medial longitudinal fasciculus. Monakow b. SYN: rubrospinal tract. muscle b. a group of muscle fibers ensheathed by connective tissue (perimysium). neurovascular b. of Walsh the anatomic structure composed of capsular arteries and veins to the prostate and cavernous nerves that provides the macroscopic landmark used during nerve-sparing radical pelvic surgery. oblique b. of pons SYN: oblique pontine fasciculus. olfactory b. a fiber system, described by E. Zuckerkandl as “Reichbündel,” descending from the transparent septum in front of the anterior commissure toward the base of the forebrain; it contains precommissural fibers of the fornix, fibers from the septum to the hypothalamus and innominate substance, as well as fibers ascending to the septum and hippocampus from the hypothalamus and midbrain; it bears no special relation to the sense of smell. olivocochlear b. olivocochlear tract. Pick b. a b. of nerve fibers recurving rostralward from the pyramidal tract in the medulla oblongata, and believed to consist of corticonuclear fibers. posterior longitudinal b. SYN: medial longitudinal fasciculus. precommissural b. olfactory b.. predorsal b. SYN: tectospinal tract. b. of Rasmussen SYN: olivocochlear tract. Rathke bundles SYN: trabeculae carneae (of right and left ventricles), under trabecula. retroflex b. of Meynert SYN: retroflex fasciculus. right b. of atrioventricular b. [TA] the right leg or branch of the atrioventricular b. that diverges from the left crus just below the membranous portion of the interventricular septum to descend the septal wall of the right ventricle and ramify beneath the endocardium. SYN: crus dextrum fasciculi atrioventricularis [TA] , right crus of atrioventricular b.. Schütz b. SYN: dorsal longitudinal fasciculus. solitary b. SYN: solitary tract. tendon b. a group of tendon fibers surrounded by a sheath of irregular connective tissue (peritendineum). Türck b. SYN: anterior corticospinal tract. uncinate b. of Russell SYN: uncinate fasciculus of cerebellum. Vicq d'Azyr b. SYN: mammillothalamic fasciculus.

bungarotoxins (bung′ga-ro-tok′sinz)
Constituent proteins of the venom of the South Asian banded krait Bungarus multicinctus, a snake of the Elapidae family. Used as pharmacologic tools in studying neuromuscular function.

bungpagga (bung-pag′a)
SYN: tropical pyomyositis.

bunion (bun′yun)
A localized swelling at either the medial or dorsal aspect of the first metatarsophalangeal joint, caused by an inflammatory bursa; a medial b. is usually associated with hallux valgus. [O.F. buigne, bump on the head]

bunionectomy (bun-yun-ek′to-me)
Excision of a bunion. Keller b. excision of the proximal portion of the proximal phalanx of the first toe. Mayo b. excision of the head of the first metatarsal.

Sterling, U.S. surgeon, 1882–1957. See B. suture, Paul-B. test.

bunodont (boo′no-dont)
Having molar teeth with rounded or low conical cusps, in contrast to lophodont. [G. bounos, mound, + odous (odont-), tooth]

bunolol hydrochloride (bu′no-lol)
A β-adrenergic blocking agent for treatment of cardiac arrhythmias.

bunolophodont (boo-no-lof′o-dont)
Having molar teeth with transverse ridges and rounded cusps on the occlusal surface. [G. bunos, mound, + lophos, ridge, + odous, tooth]

bunoselenodont (boo′no-se-len′o-dont)
Having molar teeth with crescentic ridges and rounded cusps on the occlusal surface. [bunos, + selene, moon, + odous, tooth]

Bunostomum (bu-no-sto′mum)
A genus of hookworms (family Ancylostomatidae, subfamily Necatorinae) found in cattle and other herbivores; similar to Necator. [G. bounos, hill, mound, + stoma, mouth] B. phlebotomum a species that occurs in cattle, sheep, and some wild ruminants in many parts of the world. B. trigonocephalum a cosmopolitan hookworm species in the small intestines of sheep and goats.

Robert W., German chemist and physicist, 1811–1899. See B. burner, B. solubility coefficient, B.-Roscoe law.

Bunsen burner
A gas lamp supplied with lateral openings admitting sufficient air so that the carbon is completely burned, thus giving a very hot but only slightly luminous flame. [RW Bunsen, 1811–1899]

Bunyaviridae (bun-ya-vir′i-de)
A family of arboviruses composed of more than 200 virus serotypes and containing at least five genera: Bunyavirus, Hantavirus, Phlebovirus, Nairovirus, and Tospovirus. Virions in all genera except Hantavirus replicate in arthropods. Virions are 80–120 nm in diameter, sensitive to lipid solvents and detergents, and enveloped with glycopolypeptide surface projections; the nucleocapsid is of helical symmetry containing 3 molecules of single-stranded RNA (MW 5–8 × 106). [Bunyamwere, Uganda]

Bunyavirus (bun′ya-vi-rus)
A virus in the genus of the family Bunyaviridae that includes at least 160 types, i.e., California encephalitis virus and LaCrosse encephalitis virus.

buphthalmia, buphthalmus, buphthalmos (boof-thal′me-a, -thal′mus, -thal′mos)
An affection of infancy, marked by an increase of intraocular pressure with enlargement of the eyeball. SYN: congenital glaucoma, hydrophthalmia, hydrophthalmos, hydrophthalmus. [G. bous, ox, + ophthalmos, eye]

bupivacaine (bu-piv′a-kan)
A potent, long-acting local anesthetic used in regional anesthesia, joint and trigger point injections.

buprenorphine hydrochloride (boo-pre-nor′fen)
A semisynthetic opioid analgesic used for relief of moderate to severe pain.

bupropion hydrochloride (boo-pro′pe-on)
An antidepressant. Presently widely used as an aid to smoking cessation.

bur (bur)
1. A rotary cutting instrument. 2. In ophthalmology, a device used to remove rust rings embedded in the cornea. SYN: burr. cross-cut b. a b. with blades located at right angles to its long axis. end-cutting b. a b. with blades only on its end. finishing b. a b. with numerous fine cutting blades placed close together; used to contour metallic restorations. fissure b. a cylindrical or tapered rotary cutting tool intended for extending or widening fissures in a tooth, as for general surface reduction of tooth substance. inverted cone b. a rotary cutting instrument in the shape of a truncated cone with the smaller end attached to the shaft; generally used for entering carious pits or creating undercuts in cavity preparations. round b. a dental b. with the cutting blades spherically arranged.

H., 19th century German chemist. See B.-Liebermann reaction, Liebermann-B. test.

Karl F., German anatomist and physiologist, 1776–1847. See B. column, B. fasciculus, B. nucleus, B. tract.

burden (ber′den)
See body b.. clinical b. a b. that differs from genetic b. mainly in the added component of morbidity; a trait that is neither a clinical or a genetic lethal may be grossly disabling. genetic b. the genetic debt due to harmful mutation but as yet undischarged. (In a large population of fixed size every mutation with diminished genetic fitness will eventually become extinct and depending on the details of inheritance and phenotype must be paid for by a fixed number of genetic deaths per mutation, the genetic debt.) global b. of disease mathematical measure of loss of healthy life years due to disabling diseases in a country's population. SEE ALSO: disability-adjusted life years, under year.

buret, burette (boo-ret′)
A graduated glass tube with a tap as its lower end; used for measuring liquids in volumetric chemical analyses. [Fr.]

Max T.F., German physician, *1885. See B.-Grütz syndrome, B.-Grütz disease.

Burger triangle
See under triangle.

Dean, U.S. scientist, *1904. See Lineweaver-B. equation, Lineweaver-B. plot.

Burkholderia (burk-hol-der′e-a)
A genus of motile, non–spore-forming Gram-negative rods, containing significant species of human pathogens formerly classified as members of the genus Pseudomonas. B. cepacia a bacterial species found in rotted onions and in clinical specimens; commonly found in respiratory secretions in patients with cystic fibrosis, it is frequently resistant to many antibiotics. SYN: Pseudomonas cepacia. B. mallei a bacterial species infectious to horses and donkeys, causing glanders and farcy. SYN: Pseudomonas mallei. B. pseudomallei a species found in cases of melioidosis in humans and other animals and in soil and water in tropical regions. SYN: Pseudomonas pseudomallei.

Denis P., British physician in Uganda, 1911–1993. See B. lymphoma.

Burlew disk
See under disk.

Burlew wheel
See under wheel.

Joshua Harold, 1892–1981. See B. and Rand theory.

burn (bern)
1. To cause a lesion by heat or a similar lesion by some other agent. 2. A sensation of pain caused by excessive heat, or similar pain from any cause. 3. A lesion caused by heat or any cauterizing agent, including friction, caustic agents, electricity, or electromagnetic energy; types of burns resulting from different agents are relatively specific and diagnostic. The division of burns into three degrees (first degree, second degree, and third degree) reflects the severity of skin damage (erythema, blisters, charring, respectively). [A.S. baernan] brush b. a b. caused by friction of a rapidly moving object against the skin or ground into the skin. chemical b. a b. due to a caustic chemical. first-degree b. a b. involving only the epidermis and causing erythema and edema without vesiculation. SYN: superficial b.. flash b. a b. due to very brief exposure to intense radiant heat; the typical b. produced by atomic explosion. full-thickness b. SYN: third-degree b.. mat b. brush b.. partial-thickness b. SYN: second-degree b.. radiation b. a b. caused by exposure to radium, x-rays, atomic energy in any form, ultraviolet rays, etc. rope b. brush b.. second-degree b. a b. involving the epidermis and dermis and usually forming blisters that may be superficial, or by deep dermal necrosis, followed by epithelial regeneration extending from the skin appendages. SYN: partial-thickness b.. superficial b. SYN: first-degree b.. thermal b. a b. caused by heat. third-degree b. a b. involving destruction of the entire skin; deep third-degree burns extend into subcutaneous fat, muscle, or bone and often cause much scarring. SYN: full-thickness b..


. . . Feedback