Medical Dictionary

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q, Q

blood flow
coenzyme Q
coulomb
electric charge
glutamine
glutaminyl
heat
long arm of a chromosome
quodque (Latin = each; every)
quantity
quaternary
pseudouridine
the second product formed in an enzyme-catalyzed reaction.

Q-banding
Q-banding stain.

Q fever
a disease characterized by high fever, chills, muscular pains, headache, and sometimes pneumonia, that is caused by a rickettsial bacterium of the genus Coxiella (C. burnetii) of which domestic animals serve as reservoirs, and that is transmitted to humans especially by inhalation of infective airborne bacteria (as in contaminated dust).

Q-TWiST
Time without symptoms or toxicity; a quality of life measurement. [acronym, quality time without symptoms or toxicity]

Q wave
the short initial downward stroke of the QRS complex in an electrocardiogram formed during the beginning of ventricular depolarization.

qat
variant of khat.

QO, QO2
Symbols for oxygen consumption.

Q10

increase in rate of a process produced by raising the temperature 10°C
rate of contraction of an excised heart approximately doubles for every 10°C ( i.e., Q10 = 2).

QCO2
Symbol for the microliters STPD of CO2 given off per milligram of tissue per hour.

-Q6
Symbol for ubiquinone-6.

-Q10
Symbol for ubiquinone-10.

QALY
Acronym for quality-adjusted life years, an adjustment that allows for prevalence of activity limitation.

q.d.
Abbreviation for L. quaque die, every day.

QF
Abbreviation for quality factor, the same as relative biologic effectiveness in radiation protection.

QH2
Symbol for ubiquinol.

q.h.
Abbreviation for L. quaque hora, every hour.

q.i.d.
Abbreviation for L. quater in die, four times a day.

q.l.
Abbreviation for L. quantum libet, as much as desired.

QNB
Abbreviation for quinuclidinyl benzilate.

Q.R.
Abbreviation for [L] quantum rectum, however much is correct.

q.s.
Abbreviation for L. quantum sufficiat or satis, as much as suffices.

quack (kwak)
SYN: charlatan. [Abbreviation of quacksalver, Dutch q., to boast + salf, cream]

quackery (kwak′er-e)
SYN: charlatanism.

quadrangular (kwah-drang′u-lar)
Having four angles. [L. quadrangularis, fr. quadrangulum, quadrangle]

quadrant (kwah′drant)
One quarter of a circle. In anatomy, roughly circular areas are divided for descriptive purposes into quadrants. The abdomen is divided into right upper and lower and left upper and lower quadrants by a horizontal and a vertical line intersecting at the umbilicus. Quadrants of the ocular fundus (superior and inferior nasal, superior and inferior temporal) are demarcated by a horizontal and a vertical line intersecting at the optic disk. The tympanic membrane is divided into anterosuperior, anteroinferior, posterosuperior, and posteroinferior quadrants by a line drawn across the diameter of the drum in the axis of the handle of the malleus and another intersecting the first at right angles at the umbo. [L. quadrans, a quarter]

quadrantanopia (kwah′drant-an-op′e-a)
Loss of vision in a quarter section of the visual field of one or both eyes; if bilateral, it may be homonymous or heteronymous, binasal or bitemporal, or crossed, e.g., involving the upper quadrant in one eye and the lower quadrant in the other. SYN: quadrantic hemianopia.

quadrate (kwah′drat)
Having four equal sides; square. [L. quadratus, square]

quadratus

quadri-
Four. [L. quattuor]

quadribasic (kwah-dri-ba′sik)
Denoting an acid having four hydrogen atoms that are replaceable by atoms or radicals of a basic character.

quadriceps (kwah′dri-seps)
SYN: four-headed muscle. [L. fr. quadri- + caput, head]

quadricepsplasty (kwah-dri-seps′plas-te)
A corrective surgical procedure on the quadriceps femoris muscle and tendon to release adhesions and improve mobility. [quadriceps + G. plastos, formed]

quadricuspid (kwah-dri-kus′pid)
SYN: tetracuspid.

quadridigitate (kwah′dri-dij′i-tat)
SYN: tetradactyl. [quadri- + L. digitus, digit]

quadrigeminal (kwah′dri-jem′i-nal)
Four-fold. [quadri- + L. geminus, twin]

quadrigeminum (kwah′dri-jem′i-num)
One of the quadrigeminal bodies.

quadrigeminus (kwah-dri-jem′i-nus)
SYN: quadruplet. [L.]

quadrigeminy (kwah′dri-jem′i-ne)
SYN: quadrigeminal rhythm.

quadriparesis (kwah′dri-pa-re′sis)
SYN: tetraparesis.

quadriplegia (kwah′dri-ple′je-a)
Paralysis of all four limbs. SYN: tetraplegia. [quadri- + G. plege, stroke]

quadriplegic (kwah′dri-ple′jik)
Pertaining to or afflicted with quadriplegia. SYN: tetraplegic.

quadripolar (kwah′dri-po′lar)
Having four poles.

quadrisect (kwah′dri-sekt)
To divide into four parts. SYN: quartisect. [quadri- + L. seco, pp. sectus, to cut]

quadrisection (kwah′dri-sek′shun)
Division into four parts.

quadritubercular (kwah′dri-too-ber′ku-lar)
Having four tubercles or cusps, as a molar tooth. [quadri- + L. tuberculum, tubercle]

quadrivalent (kwah-dri-va′lent)
Having the combining power (valency) of four. SYN: tetravalent.

quadruped (kwah′droo-ped)
A four-footed animal. [L. quattuor, four, + pes (ped-), foot]

quadruplet (kwah′drup-let, kwa-droo′plet)
One of four children born at one birth. SYN: quadrigeminus. [L. quadruplus, fourfold]

quality assurance
Programs of regular assessment of medical and nursing activities to evaluate the quality of medical care.

Quant
C. A. J., early 20th century Dutch physician. See Q. sign.

quanta (kwahn′ta)
Plural of quantum. [L.]

quantile (kwon′til)
Division of a distribution into equal, ordered subgroups; deciles are tenths, quartiles are quarters, quintiles are fifths, terciles are thirds, centiles are hundredths. [L. quantum, how much, + -ilis, adj. suffix]

quantum, pl .quanta (kwahn′tum, -ta)
1. A unit of radiant energy (ε) varying according to the frequency (ν) of the radiation. 2. A certain definite amount. [L. how much] q. mottle q. mottle. See entries under under mottle. q. rectum Q.R. [L. however much is correct] q. satis q.s. [L. however much is enough] q. sink in radiologic imaging, the stage at which statistical information reaches its lowest level because of a low photon flux. q. sufficiat q.s. [L. however much is enough] q.> vis (q.v.) q.v. [L. however much you wish]

quarantine (kwar′an-ten)
1. A period (originally 40 days) of detention of vessels and their passengers coming from an area where an infectious disease prevails. 2. To detain such vessels and their passengers until the incubation period of an infectious disease has passed. 3. A place where such vessels and their passengers are detained. 4. The isolation of a person with a known or possible contagious disease. [It. quarantina fr. L. quadraginta, forty]

quark (qwark)
A fundamental particle believed to be the primary constituent of all mesons and baryons; quarks have a charge that is a fraction of 1 electron charge and interact through electromagnetic and nuclear forces. Six varieties are thought to exist with the unusual names of up, down, strange, charmed, bottom, and top. [a word of indeterminate sense used by James Joyce in his novel Finnegans Wake]

quart (kwort)
1. A measure of fluid capacity; the fourth part of a gallon; the equivalent of 0.9468 liter. An imperial q. contains about 20% more than the ordinary q., or 1.1359 liters. 2. A dry measure holding a little more than the fluid measure. [L. quartus, fourth]

quartan (kwor′tan)
Recurring every fourth day, including the first day of an episode in the computation, i.e., after a free interval of two days. [L. quartanus, relating to a fourth (thing)] double q. denoting malaria infection with two independent groups of q. parasites, so that paroxysms occur on two successive days followed by one day without fever. triple q. denoting malaria infection with three independent groups of q. parasites, so that a paroxysm occurs every day, resembling a double tertian or a quotidian fever.

quartisect (kwor′ti-sekt)
SYN: quadrisect. [L. quartus, fourth, + seco, pp. sectus, to cut]

quartz (kworts)
A crystalline form of silicon dioxide used in chemical apparatus and in optical and electric instruments.

quasidominance (kwa-si-dom′i-nans)
Simulation of dominant inheritance of a recessive trait, e.g., a heterozygote mating with an affected homozygote resulting in the manifestation of the recessive trait generation after generation. SYN: false dominance, pseudodominance.

quasidominant (kwa-si-dom′i-nant)
Denoting a trait in an inbred pedigree that exhibits quasidominance.

quassation (kwah-sa′shun)
The breaking up of crude drug materials, such as bark and woody stems, into small pieces to facilitate extraction and other treatment. [L. quassatio, fr. quasso, pp. -atus, to shake violently, fr. quatio, to shake]

quassia (kwah′she-a)
Bitterwood, the heartwood of Picrasma excelsa (Picraena excelsa), known as Jamaica q., or of Q. amara (family Simarubaceae), known as Surinam q.; a bitter tonic; the infusion has been administered by enema in the treatment of threadworms. [Quassi, a resident of Surinam who used it as a tonic]

quater in die (kua′ter-in-de-a)
See q.i.d. [L. four times a day]

quaternary (Q) (kwah′ter-nar-e, kwah-ter′ne-re)
1. Denoting a chemical compound containing four elements; e.g., NaHSO4. Cf.:q. structure. 2. Fourth in a series. 3. Relating to organic compounds in which some central atom is attached to four functional groups; applied to the usually trivalent nitrogen in its “onium” state, R4N+, “q. nitrogen.” 4. Referring to a level of structure of macromolecules in which more than one biopolymer is present. Cf.:q. structure. [L. quaternarius, fr. quaterni, four each, fr. quattuor, four, + -arius, adj. suffix]

Quatrefages de Breau
Jean L.A. de, French naturalist, 1810–1892. See Quatrefages angle.

quazepam (kwa′ze-pam)
A benzodiazepine derivative used as a sedative and hypnotic.

quebrachine (ke-brah′chen)
An alkaloid, C21H26N2O3, from quebracho and identical with yohimbine; formerly used in cardiac dyspnea.

quebracho (ke-brah′cho)
The dried bark of a genus of trees, Aspidosperma quebrachoblanco (family Apocynaceae); has been used as a respiratory stimulant in emphysema, dyspnea, and chronic bronchitis; the two chief alkaloids are aspidospermine and quebrachine. [Port. quebrahacho, fr. quebrar, to break, + hacha, axe, referring to the hardness of the wood]

Queckenstedt
Hans, German neurophysiologist, 1876–1918. See Q.-Stookey test.

quenching (kwench′ing)
1. The process of extinguishing, removing, or diminishing a physical property such as heat or light; e.g., the cooling of a hot metal rapidly by plunging it into water or oil. 2. In beta liquid scintillation counting, the shifting of the energy spectrum from a true to a lower energy; it is caused by a variety of interfering materials in the counting solution, including foreign chemicals and coloring agents. 3. The process of stopping a chemical or enzymatic reaction. [M. E. quenchen, fr. O.E. acwencan] fluorescence q. a technique used in investigations dealing with binding of antigens (haptens) by purified antibodies, applicable in cases in which the bound antigen (hapten) absorbs (quenches) light emitted during fluorescence of protein (antibody) excited by ultraviolet light.

Quénu
Eduard A.V.A., French surgeon and anatomist, 1852–1933. See Q. hemorrhoidal plexus, Q.-Muret sign.

quercetin (kwer′se-tin)
An aglycon of quercitrin, rutin, and other glycosides; occurs usually as the 3-rhamnoside; used in the treatment of abnormal capillary fragility. SYN: meletin, sophoretin.

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