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Medical Dictionary - Dictionary of Medicine and Human Biology

Medical Dictionary


bean (ben)
The flattened seed, contained in a pod, of various leguminous plants. Beans of pharmacological significance are alphabetized by specific name. [O.E. b.]

beard [TA]
SYN: barba.

bearing (bar′ing)
A supporting point or surface. central b. in dentistry, application of forces between the maxillae and mandible at a single point located as near as possible to the center of the supporting areas of the upper and lower jaws; used for the purpose of distributing closing forces evenly throughout the areas of the supporting structures during the recording of maxillomandibular (jaw) relations and during the correction of occlusal errors.

bearing down
Expulsive effort of a parturient woman in the second stage of labor.

beat (bet)
1. To strike; to throb or pulsate. 2. A stroke, impulse, or pulsation, as of the heart or pulse. 3. Activity of a cardiac chamber produced by catching a stimulus generated elsewhere in the heart. 4. The perception of a third tone when two tones of slightly different frequencies are presented. 5. One of a series of regularly pulsating tones created by the periodic mutual reinforcement of two simultaneously sounding tones that differ slightly in frequency. [A.S. beatan] apex b. the visible and/or palpable pulsation made by the apex of the left ventricle as it strikes the chest wall in systole; normally in the fifth intercostal space, about 10 cm to the left of the median line. atrial capture b. the cardiac cycle resulting when, after a period of A-V dissociation, the atria regain control of the ventricles; atrial depolarization due to retrograde transmission from a ventricular ectopic b. or an electronically paced ventricular impulse. atrial fusion b. a b. that occurs when the atria are activated in part by the sinus impulse and in part by an ectopic or retrograde impulse from A-V junction or ventricle. automatic b. in contrast to forced b., an ectopic b. that arises de novo and is not precipitated by the preceding b.; thus escaped and parasystolic beats are automatic. SYN: automatic contraction. combination b. SYN: fusion b.. coupled beats beats (usually premature) that recur at a fixed interval from a preceding (usually normal) b.. dependent b. SYN: forced b.. Dressler b. fusion b. interrupting a ventricular tachycardia and producing a normally narrow QRS complex as a result of the fusion of two impulses, one impulse from the ventricular tachycardia and the other from a supraventricular focus; Dressler beats strongly support the diagnosis of ventricular tachycardia by interruption of it. dropped b. a heart b. that fails to appear. echo b. extrasystole produced by the return of an impulse in the heart retrograde to a focus near its origin which then returns antegradely to produce a second depolarization. ectopic b. a cardiac b. originating elsewhere than at the sinoatrial node. escape b. an automatic b., usually arising from the AV junction or ventricle, occurring after the next expected normal b. has defaulted; it is therefore always a late b., terminating a longer cycle than the normal. SYN: escape contraction. forced b. 1. an extrasystole supposedly precipitated in some way by the preceding normal b. to which it is coupled; 2. an extrasystole caused by artificial stimulation of the heart. SYN: dependent b.. fusion b. a b. triggered by more than a single electrical impulse, when the wave fronts coincide to act together on a single final pathway of activity; in the electrocardiogram, the atrial or ventricular complex when either atria or ventricles are activated jointly by two simultaneous or nearly simultaneous invading impulses. SYN: combination b., mixed b., summation b.. heart b. a complete cardiac cycle, including spread of the electrical impulse and the consequent mechanical contraction. SYN: ictus cordis. interference b. ventricular capture in forms of AV dissociation due to interference. mixed b. SYN: fusion b.. paired beats bigeminy. parasystolic b. SYN: parasystole. premature b. SYN: extrasystole. pseudofusion b. an electrocardiographic representation of a cardiac depolarization produced by superimposition of an ineffectual electronic pacemaker spike upon a QRS-complex originating from a spontaneous focus within the heart; the pacemaker spike is ineffectual because the electronic discharge, which it represents graphically, occurred within the absolute refractory period of the spontaneous b. and is therefore not indicative of pacemaker malfunction. reciprocal b. reciprocal rhythm. retrograde b. a b. occurring as an electrical activation of a portion of a heart chamber cephalad to the chamber of origin, e.g., an atrial b. triggered by an impulse originating in the ventricle. summation b. SYN: fusion b.. ventricular fusion b. a fusion b. that occurs when the ventricles are activated partly by the descending sinus or AV junctional impulse and partly by an ectopic ventricular impulse.

Joseph H.S., French physician, 1806–1865. See B. lines, under line.

Beauvaria (bo-va′re-a)
A genus of fungi (class Hyphomycetes). B. bassiana is pathogenic for insects, holds promise in the biologic control of insects, and has produced infection in humans.

becanthone hydrochloride (be-can′thon)
A schistosomicide.

Vladimir M. von, Russian neurologist, 1857–1927. See B. band, B. disease, layer of B., B. nucleus, B. sign, line of B., band of Kaes-B., B.-Mendel reflex, Mendel-B. reflex.

Claude S., U.S. surgeon, 1894–1971. See B. triad.

E.V.V., Russian physician. See Bek.

Emil G., U.S. surgeon, 1866–1932. See B. method.

Samuel W., U.S. dermatologist, 1894–1964. See B. nevus.

Peter Emil, German geneticist, *1908. See B.-type tardive muscular dystrophy, B. muscular dystrophy.

J.P. See B. disease.

Becker stain for spirochetes
See under stain.

Ernst O., German chemist, 1853–1923. See B. apparatus.

John Bruce, U.S. pathologist, *1933. See B.-Wiedemann syndrome.

Pierre A., French anatomist, 1785–1825. See ranine anastomosis, B. hernia, B. triangle.

beclomethasone dipropionate (be-klo-meth′a-son)
A topical anti-inflammatory agent; often used by inhalation in asthma.

Antoine H., French physicist and Nobel laureate, 1852–1908. See b., B. rays, under ray.

becquerel (Bq) (bek-a-rel′)
The SI unit of measurement of radioactivity, equal to 1 disintegration per second; 1 Bq = 0.027 × 10−9 Ci. [AH B.]

1. In anatomy, a base or structure that supports another structure. 2. A piece of furniture used for rest, recuperation, or treatment. b. of breast structures against which the posterior surface of the breast lies; includes mainly the pectoralis major muscle, but also some serratus anterior and external abdominal oblique muscle; extends from second to sixth rib, and from parasternal to anterior axillary lines. capillary b. the capillaries considered collectively and their volume capacity for blood. fracture b. a narrow, extra-firm b. for treatment of fractures; usually incorporates an overhead frame for traction apparatus. Gatch b. a b. with divided sections for independent elevation of a patient's head and knees. mud b. a b. in which the mattress consists of semiliquid mud made from special clays, covered with a sheet of plastic material; used to widely distribute the pressure of the body weight over the dependent surface, for patients with burns or large anesthetic areas. nail b. SYN: nail matrix. parotid b. the structures which surround and contact the parotid, forming the boundaries of the parotid space: anteriorly, the ramus of the mandible flanked by the masseter and medial pterygoid muscles; medially, the pharyngeal wall, carotid sheath and structures originating from the styloid process; posteriorly, the mastoid process, sternocleidomastoid muscle, and posterior belly of the digastric muscle; superiorly, the temporomandibular joint and the tympanic bone and cartilaginous portion of the external acoustic meatus. b. of parotid gland SYN: parotid space. b. of stomach the structures against which the posteroinferior surface of the stomach lies, and from which it is separated, for the main part, by the omental bursa; includes diaphragm, left suprarenal gland, upper part of left kidney, splenic artery, anterior aspect of pancreatic body and tail, left colic flexure, and transverse mesocolon. water b. a mattress in the form of a closed rubber bag filled with water; used to prevent or treat pressure sores by equalizing the distribution of the patient's weight against the support.

See entries under Cimex.

bedlam (bed′lam)
1. Pejorative colloquialism for a mental hospital or institution. 2. A place or scene of wild or riotous behavior. 3. A disturbing uproar. [corruption or contraction of St. Mary of Bethlehem Hospital in London]

Blahoslav, 20th century Czech pathologist. See B. tumor.

Alois, Austrian physician, 1816–1888. See B. aphthae, under aphtha.

bedsore (bed′sor)
SYN: decubitus ulcer.

SYN: nocturnal enuresis.

An insect of the genus Apis; the honeybee, A. mellifica, is the source of honey and wax. [A.S. beó, bi]

beech oil
SYN: beechwood tar.

beechwood tar (bech′wud)
A thick, oily, dark brown liquid with the odor of creosote; largely used as a source of creosote. SYN: beech oil.

August, German physicist, 1825–1863. See B.-Lambert law, B. law.

Georg J., Austrian ophthalmologist, 1763–1821. See B. knife.

beeswax (bez′waks)
SYN: wax (1) . white b. SYN: white wax.

beeturia (be-too′re-a)
Urinary excretion of betacyanin after ingestion of beets, found in most iron-deficient individuals and in some normal persons. SYN: betacyaninuria.

Charles E., English neurologist, 1854–1908. See B. sign.

James, Scottish physician, 1798–1869.

P. Raymond, Australian orthodontist, *1898. See B. light wire differential force technique.

Béguez César
Antonio, Cuban pediatrician. See B. disease.

behavior (be-hav′yer)
1. Any response emitted by or elicited from an organism. 2. Any mental or motor act or activity. 3. Specifically, parts of a total response pattern. [M.E., fr. O. Fr. avoir, to have] adaptive b. any b. that enables an organism to adjust to a particular situation or environment. appetitive b. movement of an organism toward a certain type of stimulus, such as food. Cf.:aversive b.. aversive b. movement of an organism away from a certain type of stimulus, such as electric shock. Cf.:appetitive b.. coronary-prone b. hostile b. that increases the risk of heart disease. health b. combination of knowledge, practices, and attitudes that together contribute to motivate the actions we take regarding health. hookean b. the b. of a perfectly elastic body; i.e., the strain is directly proportional to the stress. SEE ALSO: Hooke law. hostile b. b. that increases the risk of heart disease. molar b. in psychology, b. described in large response units rather than smaller ones. Cf.:molecular b.. molecular b. in psychology, b. described in small response units rather than larger ones; a specific response. Cf.:molar b.. obsessive b. the repetitive stylized b. seen in obsessive-compulsive neurosis. operant b. b. whose continuation and frequency is determined by its consequences on the doer; central element of behavioral conditioning theory. See conditioning. passive-aggressive b. apparently compliant b., with intrinsic obstructive or stubborn qualities, to cover deeply felt aggressive feelings that cannot be more directly expressed. respondent b. b. in response to a specific stimulus; usually associated with classical conditioning. See conditioning. ritualistic b. automatic b. of psychogenic or cultural origin. target b. 1. SYN: operant. 2. in b. modification therapy, the prescribed b.. type A b. a b. pattern characterized by aggressiveness, ambitiousness, restlessness, and a strong sense of time urgency. New research has revealed that it is hostility, which can be commingled with other type A traits, that is associated with increased risk for coronary heart disease. type B b. a b. pattern characterized by the absence or obverse of type A b. characteristics.

behavioral (be-hav′yer-al)
Pertaining to behavior.

behavioral sciences
A collective term for those disciplines or branches of science, such as psychology, sociology, and anthropology, and which derive their theories, concepts, and approaches from the observation and study of the behavior of living organisms.

behaviorism (be-hav′yer-izm)
A branch of psychology that formulates, through systematic observation and experimentation, the laws and principles that underlie the behavior of humans and animals; its major contributions have been made in the areas of conditioning and learning. SYN: behavioral psychology.

behaviorist (be-hav′yer-ist)
An adherent of behaviorism.

Hulusi, Turkish dermatologist, 1889–1948. See B. disease, B. syndrome.

behenic acid (be-hen′ik)
CH3(CH2)20COOH;a constituent of most fats and fish oils; large amounts are found in jamba, mustard seed, rapeseed oils, and cerebrosides. SYN: n-docosanoic acid.

Carl J.P., German ophthalmologist, 1874–1943. See B. disease, B. syndrome.

Emil A. von, German bacteriologist and Nobel laureate, 1854–1917. See B. law.

Abbreviation for butanol-extractable iodine.

Nonvenereal endemic syphilis now found chiefly among Arab children; apparently due to Treponema pallidum. SEE ALSO: nonvenereal syphilis. [Ar. bajlah]

Bek (or Beck)
E.V., Russian physician. See Kashin-B. disease.

Georg von, Hungarian biophysicist in U.S. and Nobel laureate, 1899–1972. See B. audiometer, B. audiometry.

Unit expressing the relative intensity of a sound. The intensity in bels is the logarithm (to the base 10) of the ratio of the power of the sound to that of a reference sound. Ordinarily, the reference sound is assumed to be one with a power of 10−16 watts per sq cm, approximately the threshold of a normal human ear at 1000 Hz. [A.G. Bell, Scottish-U.S. scientist, 1847–1922]

SYN: eructation. [A.S. baelcian]

belemnoid (be-lem′noyd)
Dart-shaped. [G. belemnon, a dart, + eidos, resemblance]

John, Scottish surgeon and anatomist, 1763–1820. See B. muscle.

Sir Charles, Scottish surgeon, anatomist, and physiologist, 1774–1842. See B. law, B.-Magendie law, B. respiratory nerve, B. palsy, B. spasm, external respiratory nerve of B..

belladonna (bel-a-don′a)
Atropa b. (family Solanaceae); a perennial herb with dark purple flowers and shining purplish-black berries; the leaves (0.3% b. alkaloids) and root (0.5% b. alkaloids) orginally were source of atropine and related alkaloids, which are anticholinergic. B. is used as a powder (0.3% b. alkaloids, calculated as hyoscyamine) and tincture in diarrhea, asthma, colic, and hyperacidity. SYN: deadly nightshade. [It. bella, beautiful, + donna, lady]

belladonnine (bel-a-don′en)
An artificial alkaloid derived from atropine by warming with hydrochloric acid.

bell-crowned (bel′krownd)
Denoting a tooth the crown of which has a cross-sectional diameter much greater than that of the neck.

belle indifférence
See la b..

Lorenzo, Italian physician and anatomist, 1643–1704. See B. ducts, under duct, B. ligament.

belly (bel′e)
1. The abdomen. 2. The wide swelling part of a muscle. SYN: venter (2) [TA] . 3. Popularly, the stomach or womb. [O.E. belig, bag] anterior b. of digastric muscle [TA] the portion of the digastric muscle that extends anteriorly from the intermediate tendon, and attaches to the posterior aspect of the mandible. SYN: venter anterior musculi digastrici [TA] . bellies of digastric muscle anterior b. of digastric muscle, posterior b. of digastric muscle. frontal b. of occipitofrontalis muscle [TA] the anterior b. of the occipitofrontalis muscle. See occipitofrontalis (muscle). SYN: venter frontalis musculi occipitofrontalis [TA] , frontalis muscle. inferior b. of omohyoid muscle [TA] the inferior b. of the omohyoid muscle, attached to the superior border of the scapula. SYN: venter inferior musculi omohyoidei [TA] . occipital b. of occipitofrontalis muscle [TA] the posterior b. of the occipitofrontalis muscle. See occipitofrontalis (muscle). SYN: venter occipitalis musculi occipitofrontalis [TA] , occipitalis muscle. bellies of omohyoid muscle inferior b. of omohyoid muscle, superior b. of omohyoid muscle. posterior b. of digastric muscle [TA] portion of digastric muscle posterior to the intermediate tendon, attaching to the digastric groove of the temporal bone. SYN: venter posterior musculi digastrici [TA] . prune b. SYN: abdominal muscle deficiency syndrome. superior b. of omohyoid muscle [TA] the superior b. of the omohyoid muscle, attached to the hyoid bone. SYN: venter superior musculi omohyoidei [TA] .


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