Medical Dictionary

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coccygodynia (kok′si-go-din′e-a)
SYN: coccydynia. [coccyx + G. odyne, pain]

coccygotomy (kok-se-got′o-me)
Operation for freeing the coccyx from its attachments. [coccyx + G. tome, a cutting]

coccyodynia (kok′se-o-din′e-a)
SYN: coccydynia.

coccyx, gen. coccygis, pl .coccyges (kok′siks, -si-jis, -si-jes) [TA]
The small bone at the end of the vertebral column in humans, formed by the fusion of four rudimentary vertebrae; it articulates above with the sacrum. SYN: os coccygis [TA] , coccygeal bone, tail bone. [G. kokkyx, a cuckoo, the c.]

cochineal (kotch′i-nel) [C.I. 75470]
The dried female insects, Coccus cacti, enclosing the young larvae, or the dried female insect, Dactylopius coccus, containing eggs and larvae, from which coccinellin is obtained; used as a red coloring agent and a stain. See carmine. SYN: coccinella, coccus (2) . [O.Sp. cochinilla, wood louse, fr. G. kokkinos, berry]

cochlea, pl .cochleae (kok′le-a, le-e) [TA]
A conical cavity in the petrous portion of the temporal bone, forming one of the divisions of the labyrinth or internal ear. It consists of a spiral canal making two and a half turns around a central core of spongy bone, the modiolus; this spiral canal of the c. contains the membranous c., or cochlear duct, in which is the spiral organ (Corti). [L. snail shell] membranous c. SYN: cochlear duct.

cochlear (kok′le-ar)
Relating to the cochlea. c. microphonic (kok′le-ar mi-kro-fon′ik) bioelectric potentials produced by the hair cells of the organ of Corti in response to sound that faithfully represent the frequency and intensity of the acoustic stimulation. SYN: c. potential, Wever-Bray phenomenon.

cochleare (ko-kle′a, kok-le-a′re)
A spoon. [L.] c. amplum a tablespoonful. [L.] c. magnum a tablespoonful. [L.] c. medium a dessertspoonful. [L.] c. modicum a dessertspoonful. [L.] c. parvum a teaspoonful. [L.]

cochleariform (kok-le-ar′i-form)
Spoon-shaped. [L. cochleare, spoon, + forma, form]

cochleate (kok′le-at)
1. Resembling a snail shell. 2. Denoting the appearance of a form of plate culture. [L. cochlea, a snail shell]

cochleitis (ko-kle-i′tis)
Inflammation of the cochlea. [cochlea + G. -itis, inflammatio]

cochleosacculotomy (kok′le-o-sac-u-lot′o-me)
An operation for Ménière disease performed through the round window to create a shunt between the cochlear duct and the saccule.

cochleotopic (ko-kle-o-top′ik)
Referring to the frequency-responsive organization of the central auditory pathways in the brain. [cochlea + G. topos, place, + -ic]

cochleovestibular (kok′le-o-ves-tib′u-lar)
Relating to the cochlea and the vestibule of the ear.

Cochliomyia (kok′le-o-mi′ya)
A genus of fleshflies (family Calliphoridae) whose larvae develop in decaying flesh or carrion or in wounds or sores. C. americana incorrect name for C. hominivorax. C. hominivorax the screw-worm fly, a species that is a serious pest of livestock from Mexico to Argentina and is the primary cause of myiasis in the western hemisphere; attracted by fresh blood, it deposits eggs on wounds, tick bites, or intact moist areas of the body, and the larvae invade living tissues, causing severe myiasis and often death; it is known to attack humans, especially in the nose, although wounds, eyes, and other body openings have also been attacked.

Cochrane
A.L., British epidemiologist, 1909–1988. See C. collaboration.

cocillana (ko′se-lah′na)
The dried bark of Guarea rusbyi, a Bolivia tree, used as an expectorant in bronchitis.

Cockayne
Edward A., British physician, 1880–1956. See C. disease, C. syndrome, Weber-C. syndrome.

cocktail (kok′tal)
A mixture that includes several ingredients or drugs. Brompton c. a c. of morphine and cocaine usually used for analgesia in terminal cancer patients; the formulations vary, but typically it contains 15 mg of morphine hydrochoride and 10 mg of cocaine hydrochloride per 10 ml of the c.. [Brompton Chest Hospital, London, England, where developed] Philadelphia c. SYN: Rivers c.. Rivers c. an intravenous slow injection of from 1000 to 2000 ml of 10% dextrose in isotonic saline to which thiamine hydrochloride and 25 units of insulin are added; used in acute alcoholism. SYN: Philadelphia c..

cocoa (ko′ko)
A powder prepared from the roasted kernels of the ripe seed of Theobroma cacao (family Sterculiaceae); used in the preparation of c. syrup, a flavoring agent. SEE ALSO: cacao.

coconsciousness (ko-kon′shus-nes)
1. A splitting of consciousness into two streams. 2. Awareness by one personality of the thoughts of another personality in dissociative disorder.

coconversion (ko′kon-ver′shun)
The simultaneous correction of two sites on DNA during gene conversion.

cocto-
Prefix indicating boiled or modified by heat. [L. coctus, cooked]

coctolabile (kok-to-la′bil, -bil)
Subject to alteration or destruction when exposed to the temperature of boiling water.

coctostabile, coctostable (kok-to-sta′bil, -bil; -sta′bl)
Resisting the temperature of boiling water without alteration or destruction.

code (kod)
1. A set of rules, principles, or ethics. 2. Any system devised to convey information or facilitate communication. 3. Term used in hospitals to describe an emergency requiring situation trained members of the staff, such as a cardiopulmonary resuscitation team, or the signal to summon such a team. 4. A numeric system for ordering and classifying information, e.g., about diagnostic categories. [L. codex, book] genetic c. the genetic information carried by the specific DNA molecules of the chromosomes; specifically, the system whereby particular combinations of three consecutive nucleotides in a DNA molecule control the insertion of one particular amino acid in equivalent places in a protein molecule. The genetic c. is almost universal throughout the prokaryotic, plant, and animal kingdoms. There are two known exceptions. In ciliated protozoans, the triplets AGA and AGG are read as termination signals instead of as l-arginine. This is also true of the human mitochondrial c., which, in addition, uses AUA as a c. for l-methionine (instead of isoleucine) and UGA for l-tryptophan (instead of a termination signal). soundex c. a sequence of letters used for recording names phonetically, especially in record linkage.

codeine (ko′den)
Obtained from opium, which contains 0.7 to 2.5%, but usually made from morphine. Used as an analgesic and antitussive; drug dependence (physical and psychic) may develop, but c. is less liable to produce addiction than is morphine; c. is biotransformed to morphine, which accounts for most of c.'s effects. SYN: methylmorphine. [G. kodeia, head, poppy head]

Codex medicamentarius (ko′deks med′i-ka-men-tar′e-us)
The official title of the French Pharmacopeia. [L. a book pertaining to drugs]

coding
Translation of information, e.g., diagnoses, questionnaire responses, into numbered categories for entry into a data processing system. place c. frequency c. as determined by the activation of the organ of Corti from the base to the apex of the cochlea in a gradation with higher frequencies transmitted from near the base and lower frequencies from near the apex.

cod liver oil
The partially destearinated fixed oil extracted from the fresh livers of the codfish (Gadus morrhuae) and other species of the family Gadidae, containing vitamins A and D; used as a supplementary source of vitamins A and D.

Codman
Ernest Amory, U.S. surgeon, 1869–1940. See C. triangle, C. tumor.

codogenic (ko-do-jen-ik)
Formed by a code; specifically, the genetic code.

codominant (ko-dom′i-nant)
In genetics, denoting an equal degree of dominance of two genes, both being expressed in the phenotype of the individual; e.g., genes A and B of the ABO blood group are c.; individuals with both are type AB.

codon (ko′don)
A set of three consecutive nucleotides in a strand of DNA or RNA that provides the genetic information to code for a specific amino acid which will be incorporated into a protein chain or serve as a termination signal. SYN: triplet (3) . [code + -on] amber c. the termination c. UAG. initiating c. the trinucleotide AUG (or sometimes GUG) that codes for the first amino acid in protein sequences, formylmethionine; the latter is often removed post-transcriptionally. SYN: start c.. initiation c. a specific mRNA sequence (usually AUG, but sometimes GUG) that is the signal for the addition of fMet-tRNA and the beginning of translation. nonsense c. SYN: termination c.. ochre c. the termination c. UAA. opal c. SYN: umber c.. punctuation c. SYN: termination c.. start c. SYN: initiating c.. stop c. SYN: termination c.. termination c. trinucleotide sequence (UAA, UGA, or UAG) that specifies the end of translation or transcription. Cf.:amber c., ochre c., umber c.. SYN: nonsense c., punctuation c., stop c., termination sequence, termination signal. umber c. the termination c. UGA. SYN: opal c..

coe-
For words so beginning, and not found here, see ce-.

coefficient (ko-e-fish′ent)
1. The expression of the amount or degree of any quality possessed by a substance, or of the degree of physical or chemical change normally occurring in that substance under stated conditions. 2. The ratio or factor that relates a quantity observed under one set of conditions to that observed under standard conditions, usually when all variables are either 1 or a simple power of 10. [L. co- + efficio (exfacio), to accomplish] absorption c. 1. the milliliters of a gas at standard temperature and pressure that will saturate 100 mL of liquid; 2. the amount of light absorbed in passing through 1 cm of a 1 molar solution of a given substance, expressed as a constant in Beer-Lambert law; Cf.:specific absorption c.. 3. a measure of the rate of decrease of intensity of an x-ray beam in its passage through a substance, resulting from a combination of scattering and conversion to other forms of energy. activity c. (γ) activity (2) . biological c. rarely used term denoting the energy expended by the body at rest. Bunsen solubility c. (α) the milliliters of gas STPD dissolved per milliliter of liquid and per atmosphere (760 mm Hg) partial pressure of the gas at any given temperature. c. of consanguinity SYN: c. of inbreeding. correlation c. a measure of association that indicates the degree to which two variables have a linear relationship; this c., represented by the letter r, can vary between +1 and −1; when r = +1, there is a perfect positive linear relationship in which one variable relates directly with the other; when r = −1, there is a perfect negative linear relationship between the variables. creatinine c. the number of milligrams of creatinine excreted daily per kilogram of body weight. diffusion c. the mass of material diffusing across a unit area in unit time under a concentration gradient of unity. SYN: diffusion constant. distribution c. the ratio of concentrations of a substance in two immiscible phases at equilibrium; the basis of many chromatographic separation procedures. SYN: partition c.. economic c. in growth and cultivation of microorganisms, the ratio of the mass produced to the substrate consumed. extinction c. (ε) SYN: specific absorption c.. extraction c. the percentage of a substance removed from the blood or plasma in a single passage through a tissue; e.g., the extraction c. for p-aminohippuric acid (PAH) in the kidney is the difference between arterial and renal venous plasma PAH concentrations, divided by the arterial plasma PAH concentration. filtration c. a measure of a membrane's permeability to water; specifically, the volume of fluid filtered in unit time through a unit area of membrane per unit pressure difference, taking into account both hydraulic and osmotic pressures. Hill c. the slope of the line in a Hill plot; a measure of the degree of cooperativity. SYN: Hill constant. hygienic laboratory c. SYN: Rideal-Walker c.. c. of inbreeding the probability that the progeny of a consanguineous marriage will be homozygous for a specific autosomal allele derived from a common ancestor. SYN: c. of consanguinity. isotonic c. the amount of salts in the blood plasma, or the amount that should be added to distilled water in order to prepare an isotonic solution. c. of kinship the probability that two genes at the same locus, picked at random from each of two individuals, are identical by descent. lethal c. that concentration of disinfectant that kills bacteria at 20–25°C in the shortest period of time. linear absorption c. that fraction of ionizing radiation absorbed in a unit thickness of a substance or tissue. SEE ALSO: absorption c. (3) . Cf.:attenuation. Long c. SYN: Long formula. molar absorption c. (ε) absorbance (of light) per unit path length (usually the centimeter) and per unit of concentration (moles per liter); a fundamental unit in spectrophotometry. SYN: absorbancy index (2) , absorptivity (2) , molar absorbancy index, molar absorptivity, molar extinction c.. molar extinction c. SYN: molar absorption c.. Ostwald solubility c. (Λ) the milliliters of gas dissolved per milliliter of liquid and per atmosphere (760 mm Hg) partial pressure of the gas at any given temperature. This differs from Bunsen solubility c. (α) in that the amount of dissolved gas is expressed in terms of its volume at the temperature of the experiment, instead of STPD. Thus, λ = α (1 + 0.00367t), where t = temperature in degrees Celsius. oxygen utilization c. the extraction c. for oxygen in any given tissue. partition c. SYN: distribution c.. permeability c. a c. associated with simple diffusion through a membrane that is proportional to the partition c. and the diffusion c. and inversely proportional to membrane thickness. phenol c. SYN: Rideal-Walker c.. Poiseuille viscosity c. an expression of the viscosity as determined by the capillary tube method; the c. η = (πPr4t8vl), where P is the pressure difference between the inlet and outlet of the tube, r the radius of the tube, l its length, and v the volume of liquid delivered in the time t. If volume is in cubic centimeters, time is in seconds, and l and r are in centimeters, then η will be in poise. reflection c. (σ) a measure of the relative permeability of a particular membrane to a particular solute; calculated as the ratio of observed osmotic pressure to that calculated from van't Hoff law; also equal to 1 minus the ratio of the effective pore areas available to solute and to solvent. c. of relationship the probability that a gene present in one mate is also present in the other and is derived from the same source. reliability c. an index of the consistency of measurement often based on the correlation between scores obtained on the initial test and a retest (test-retest reliability) or between scores on two similar forms of the same test (equivalent-form reliability). respiratory c. SYN: respiratory quotient. Rideal-Walker c. a figure expressing the disinfecting power of any substance; it is obtained by dividing the figure indicating the degree of dilution of the disinfectant that kills a microorganism in a given time by that indicating the degree of dilution of phenol that kills the organism in the same space of time under similar conditions. SYN: hygienic laboratory c., phenol c.. sedimentation c. (s) SYN: sedimentation constant. selection c. (s) the proportion of progeny or potential progeny not surviving to sexual maturity; usually defined artificially by expressing the fitness of a phenotype as a fraction of the mean or optimal fitness to give the relative fitness, and subtracting this fraction from unity. If the mean size of family in the population is 3.2 and that for a particular genotype is 2.4 then the fitness of the phenotype is 2.4/3.2 = 0.75 and the selection c. = 1 − 0.75 = .25. specific absorption c. (a) absorbance (of light) per unit path length (usually the centimeter) and per unit of mass concentration. Cf.:molar absorption c.. SYN: absorbancy index (1) , absorptivity (1) , extinction c., specific extinction. temperature c. the fractional change in any physical property per degree rise in temperature. ultrafiltration c. the filtration c. of a semipermeable membrane. c. of variation (CV) the ratio of the standard deviation to the mean. velocity c. the rate of transformation of a unit mass of substance in a chemical reaction. c. of viscosity the value of the force per unit area required to maintain a unit relative velocity between two parallel planes a unit distance apart.

Coelenterata (se-len-te-ra′ta)
One of the major phyla of invertebrates, to which such forms as jellyfish belong.

coelenterate (se-len′ter-at)
Common name for members of the Coelenterata.

coelom (se′lom)
SYN: body cavity.

coenesthesia (ko-en-es-the′ze-a)
SYN: cenesthesia.

coeno-
Shared in common. SEE ALSO: ceno-. [G. koinos, common]

coenocyte (se′no-sit)
SYN: cenocyte.

coenocytic (se-no-sit′ik)
SYN: cenocytic.

coenurosis (se-noo-ro′sis)
SYN: cenurosis.

Coenurus (se-noo′rus)
Former generic name, now used to designate larval forms of taenioid cestodes in which a bladder is formed with a number of invaginated scoleces developing within; distinguished from a hydatid cyst by the absence of free-floating daughter cyst colonies budded off within the bladder; C. larvae are found in members of the genus Multiceps. [G. koinos, common, + oura, tail] C. cerebralis the c. larvae of the tapeworm Multiceps multiceps, found in the brain and spinal cord of sheep, goats, and other ruminants (a few have been recorded in humans); adults are found in the intestine of dogs, foxes, coyotes, and jackals. C. serialis the c. larvae of the tapeworm Multiceps serialis, found in subcutaneous and intramuscular tissues of rabbits and hares (a few have been recorded in humans); adult worms are found in the intestine of dogs, foxes, and jackals.

coenzyme (ko-en′zim)
A substance (excluding solo metal ions) that enhances or is necessary for the action of enzymes; coenzymes are of smaller molecular size than the enzymes themselves, are dialyzable and relatively heat-stable, and are usually easily dissociable from the protein portion of the enzyme; several vitamins are c. precursors. SYN: cofactor (1) .

coenzyme A (CoA)
A coenzyme containing pantothenic acid, adenosine 3′-phosphate 5′-pyrophosphate, and cysteamine; involved in the transfer of acyl groups, notably in transacetylations.

coenzyme F (ko-en′zim)
SYN: tetrahydrofolic acid.

coenzyme Q (CoQ, Q)
Quinones with isoprenoid side chains (specifically, ubiquinones) that mediate electron transfer between cytochrome b and cytochrome c; chemically similar to vitamins E and K, and to other tocopherols, quinones, and tocols.

coenzyme R
SYN: biotin.

coeur (koor)
SYN: heart. [Fr.] c. en sabot (awn sah-bo′) the radiographic configuration of the heart in the tetralogy of Fallot; the elevated apex gives a silhouette like that of a wooden shoe. SYN: sabot heart, wooden-shoe heart.

coevolution (ko-ev-o-loo′shun)
The process whereby genes or gene fragments are changing together and not diverging.

cofactor (ko′fak′ter, tor)
1. SYN: coenzyme. 2. An atom or molecule essential for the action of a large molecule; e.g., heme in hemoglobin, magnesium in chlorophyll. Solo metal ions are regarded as cofactors for proteins, but not as coenzymes. cobra venom c. equivalent in action to C3B, which means that it can activate the alternative complement pathway. molybdenum c. (mo-lib′de-num) a complex of molybdenum and molybdopterin required for a number of enzymes. A deficiency of this c. will result in lower activities of sulfite oxidase, xanthine dehydrogenase, and aldehyde oxidase causing elevated levels of sulfite, thiosulfite, xanthine, etc. platelet c. I SYN: factor VIII. platelet c. II SYN: factor IX.

Coffey
Robert, U.S. surgeon, 1869–1933. See C. suspension.

Coffin
Grange S., U.S. pediatrician, *1923. See C.-Lowry syndrome, C.-Siris syndrome.

Cogan
David G., U.S. ophthalmologist, 1908–1993. See C. syndrome, C.-Reese syndrome.

cognition (kog-ni′shun)
1. Generic term embracing the mental activities associated with thinking, learning, and memory. 2. Any process whereby one acquires knowledge. [L. cognitio]

cognitive (kog′ni-tiv)
Pertaining to cognition.

cohesion (ko-he′zhun)
The attraction between molecules or masses that holds them together. [L. co-haereo, pp. -haesus, to stick together]

Cohnheim
Julius F., German histologist, pathologist, and physiologist, 1839–1884. See C. area, C. field.

cohoba (ko-ho′ba)
A psychotomimetic hallucinogenic substance obtained from Acacia niopo (family Leguminosae), a Central American plant, Piptadenia peregrina, and other plants; among its constituents are bufotenine and dimethyltryptamine; used in native localities as snuff or enema.

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