Medical Dictionary

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crippled (krip′ld)
Denoting a person who, owing to a physical defect or injury, is partially or completely disabled. [A.S. creopan, to creep]

crisis, pl .crises (kri′sis, -sez)
1. A sudden change, usually for the better, in the course of an acute disease, in contrast to the gradual improvement by lysis. 2. A paroxysmal pain in an organ or circumscribed region of the body occurring in the course of tabetic neurosyphilis. SYN: tabetic c.. 3. A convulsive attack. [G. krisis, a separation, c.] addisonian c. SYN: acute adrenocortical insufficiency. adolescent c. the emotional turmoil often accompanying adolescence. adrenal c. SYN: acute adrenocortical insufficiency. anaphylactoid c. 1. SYN: anaphylactoid shock. 2. SYN: pseudoanaphylaxis. blast c. a sudden alteration in the status of a patient with leukemia in which the peripheral blood cells are almost exclusively blast cells of the type characteristic of leukemia; usually accompanied by a decrease in numbers of other formed elements of the blood, fever, and rapid clinical deterioration. blood c. 1. the appearance of a large number of nucleated red blood cells in the peripheral blood, accompanied by reticulocytosis and occurring in “exhausted” bone marrow in pernicious anemia and in hemolytic icterus; 2. a suddenly appearing leukocytosis, indicating a change for the better in the course of a grave blood disease. Dietl c. intermittent pain, sometimes with nausea and emesis, caused by intermittent proximal obstruction of ureter. Originally believed due to a mobile kidney that caused ureter to kink with positional changes. SYN: incarceration symptom. febrile c. the stage in a febrile disease when spontaneous defervescence occurs. gastric c. an attack, usually lasting several days, with severe pain in the abdomen or around the waist, accompanied by nausea and vomiting and occasionally diarrhea; occurs in tabetic neurosyphilis. glaucomatocyclitic c. a form of monocular secondary open-angle glaucoma due to recurrent mild cyclitis. hemolytic c. massive hemolysis with severe anemia associated with hemolytic disease such as sickle cell disease. identity c. a disorientation concerning one's sense of self, values, and role in society, often of acute onset and related to a particular and significant event in one's life. laryngeal c. an attack of paralysis of the abductor, or spasm of the adductor, muscles of the larynx with dyspnea and noisy respiration, occurring in tabetic neurosyphilis. midlife c. a point in a sequence of events during the middle years of life at which certain trends of prior and subsequent events in one's life are pondered, generally involving an aggregate of personal, career, or sexual dissatisfactions. myasthenic c. severe, life-threatening exacerbation of the manifestations of myasthenia gravis requiring intensive treatment. myelocytic c. a temporary but conspicuous and sudden increase in cells of the myelocytic series in the circulating blood. ocular c. sudden and severe pain in the eyes. oculogyric crises incapacitating attacks of upward eye rolling seen in encephalitis lethargica and with phenothiazine drugs. otolithic c. a sudden drop attack without loss of consciousness, vertigo, auditory disturbances, or autonomic manifestations. salt-depletion c. severe illness resulting from loss of sodium chloride, usually in urine ( i.e., salt-losing nephritis), in sweat following severe exercise in hot weather, or in intestinal secretions, as in cholera. Can occur as result of Addison disease or Addisonian c.; characterized by hypovolemia, hypotension. sickle cell c. sickle cell anemia. tabetic c. SYN: c. (2) . therapeutic c. a turning point leading to positive or negative change in psychiatric treatment. thyrotoxic c., thyroid c. the exacerbation of symptoms of hyperthyroidism; severe thyrotoxicosis; can follow shock or injury or thyroidectomy; marked by rapid pulse (140–170/minute), nausea, diarrhea, fever, loss of weight, extreme nervousness, and a sudden rise in the metabolic rate; coma and death may occur; occasionally the entire clinical picture is that of profound prostration, weakness, and collapse, without the phase of muscular overactivity and tachycardia. SYN: thyroid storm. vasoocclusive c. SYN: sickle cell anemia. visceral crises attacks of severe, spreading epigastric pain that occur in patients with tabetic neurosyphilis.

crispation (kris-pa′shun)
1. A “creepy” sensation due to slight, fibrillary muscular contractions. 2. Retraction of a divided artery or of muscular fibers or other tissues when cut across. [L. crispo, pp. -atus, to curl]

crista, pl .cristae (kris′ta, -te) [TA]
SYN: crest. [L. crest] c. ampullaris [TA] SYN: ampullary crest. c. ampullaris (ductuum semicircularium) [TA] SYN: ampullary crest (of semicircular ducts). c. arcuata cartilaginis arytenoideae [TA] SYN: arcuate crest of arytenoid cartilage. c. basalaris ductus cochlearis [TA] SYN: basal crest of cochlear duct. c. basilaris ductus cochlearis [TA] SYN: basilar crest of cochlear duct. c. buccinatoria SYN: buccinator crest. c. capitis costae [TA] SYN: crest of head of rib. c. choanalis vomeris [TA] SYN: vomerine crest of choana. c. colli costae [TA] SYN: crest of neck of rib. c. conchalis [TA] SYN: conchal crest. c. conchalis corporis maxillae [TA] SYN: conchal crest of body of maxilla. c. conchalis ossis palatini [TA] SYN: conchal crest of palatine bone. c. corporis costae [TA] SYN: crest of body of rib. cristae cutis [TA] SYN: dermal ridges, under ridge. c. dentalis SYN: dental crest. c. dividens the lower free edge of the septum secundum, forming the upper margin of the fetal foramen ovale; the limbus of the foramen ovale. c. ethmoidalis [TA] SYN: ethmoidal crest. c. ethmoidalis maxillae [TA] SYN: ethmoidal crest of maxilla. c. ethmoidalis ossis palatini [TA] SYN: ethmoidal crest of palatine bone. c. fenestrae cochleae [TA] SYN: crest of round window. c. frontalis [TA] SYN: frontal crest. c. galli [TA] the triangular midline process of the ethmoid bone extending superiorly from the cribriform plate; it gives anterior attachment to the falx cerebri. c. glutea SYN: gluteal tuberosity. c. helicis SYN: crus of helix. c. iliaca [TA] SYN: iliac crest. c. infratemporalis alaris majoris ossis sphenoidalis [TA] SYN: infratemporal crest of greater wing of sphenoid. c. intertrochanterica [TA] SYN: intertrochanteric crest. c. lacrimalis anterior [TA] SYN: anterior lacrimal crest. c. lacrimalis posterior [TA] SYN: posterior lacrimal crest. c. marginalis dentis [TA] SYN: marginal crest of tooth. cristae matricis unguis SYN: crests of nail matrix, under crest. c. medialis fibulae [TA] SYN: medial crest of fibula. cristae of mitochondria, cristae mitochondriales shelflike infoldings of the inner membrane of a mitochondrion. c. musculi supinatoris ulnae [TA] SYN: supinator crest (of ulna). c. nasalis [TA] SYN: nasal crest. c. nasalis laminae horizontalis ossis palatini [TA] SYN: nasal crest of horizontal plate of palatine bone. c. nasalis processus palatini maxillae [TA] SYN: nasal crest of palatine process of maxilla. c. obturatoria [TA] SYN: obturator crest. c. occipitalis externa [TA] SYN: external occipital crest. c. occipitalis interna [TA] SYN: internal occipital crest. c. palatina SYN: palatine crest of horizontal process of palatine bone. c. palatina laminae horizontalis ossis palatini [TA] SYN: palatine crest of horizontal process of palatine bone. c. phallica SYN: urethral crest of male. c. pubica [TA] SYN: pubic crest. c. quarta a ridge that projects into the posterior end of the lateral semicircular duct of the labyrinth. c. sacralis [TA] SYN: sacral crest. c. sacralis intermedia SYN: intermediate sacral crest. c. sacralis lateralis [TA] SYN: lateral sacral crest. c. sacralis medialis [TA] SYN: intermediate sacral crest. c. sacralis mediana [TA] SYN: median sacral crest. c. sphenoidalis [TA] SYN: sphenoidal crest. c. spiralis SYN: spiral ligament of cochlear duct. c. spiralis ductus cochlearis basal crest of cochlear duct. c. supracondylaris lateralis lateral supraepicondylar ridge. c. supracondylaris medialis medial supraepicondylar ridge. c. supraepicondylaris lateralis [TA] SYN: lateral supraepicondylar ridge. c. supraepicondylaris medialis [TA] SYN: medial supraepicondylar ridge. c. supramastoidea [TA] SYN: supramastoid crest. c. suprastyloidea radii [TA] SYN: suprastyloid crest of radius. c. supraventricularis [TA] SYN: supraventricular crest. c. temporalis mandibulae [TA] SYN: temporal crest of mandible. c. terminalis SYN: c. terminalis of right atrium. c. terminalis atrii dextri [TA] SYN: c. terminalis of right atrium. c. terminalis of right atrium [TA] a vertical crest on the interior wall of the right atrium that lies to the right of the sinus of the vena cava and separates this from the remainder of the right atrium. SYN: c. terminalis atrii dextri [TA] , c. terminalis, tenia terminalis, terminal crest. c. transversalis [TA] a crest or ridge on the occlusal surface of a tooth formed by the union of two triangular crests. SYN: transverse ridge [TA] , transverse crest (2) . c. transversa meatus acustici interni [TA] SYN: transverse crest of internal acoustic meatus. c. triangularis [TA] a crest or ridge which extends from the apex of a cusp of a premolar or molar tooth toward the central part of the occlusal surface. SYN: triangular ridge [TA] , triangular crest. c. tuberculi majoris [TA] SYN: crest of greater tubercle. c. tuberculi minoris [TA] SYN: crest of lesser tubercle. c. urethralis [TA] SYN: urethral crest. c. urethralis femininae [TA] SYN: urethral crest of female. c. urethralis masculinae [TA] SYN: urethral crest of male. c. verticalis meatus acustici interni [TA] SYN: vertical crest of internal acoustic meatus. c. vestibuli [TA] SYN: vestibular crest.

criterion, pl .criteria (kri-ter′e-on, -e-a)
1. A standard or rule for judging; usually plural (criteria) denoting a set of standards or rules. 2. In psychology, a standard such as school grades against which test scores on intelligence tests or other measured behaviors are validated. 3. A list of manifestations of a disease or disorder, a certain number of which must be present to warrant diagnosis in a given patient. [G. kriterion, a standard] Amsel criteria criteria for clinical diagnosis of bacterial vaginosis; the diagnosis is made if three of the following four criteria are positive: homogeneous discharge, pH ≥ 4.8, presence of clue cells, and amine odor with the application of KOH to the discharge. Hill's criteria of evidence a set of epidemiologic criteria that help to indicate whether a statistically significant relationship obtained in epidemiologic and other studies is a causal relationship. The criteria are consistency, specificity, strength, dose-response relationship, temporality, biologic plausibility, coherence, and capability of experimental confirmation. Temporality is the only absolute c.: the putative cause must precede the effect in time. Jones criteria criteria (proposed by T.D. Jones in 1944 and modified in 1965) used to make the diagnosis of rheumatic fever. There are five major criteria: carditis, polyarthritis, chorea, erythema marginatum, and subcutaneous nodules; minor criteria include fever, arthralgia, elevated erythrocyte sedimentation rate or C reactive protein, and prolonged PR interval on ECG. Diagnosis requires evidence of recent group A β-hemolytic streptococcal infection, plus two major and one minor criteria, or one major and two minor criteria; revised Jones criteria allow the diagnosis when indolent carditis or chorea exists with no other cause, or in patients with a previous history of rheumatic fever who have one major or two minor criteria in association with a recent streptococcal infection. Spiegelberg criteria (for diagnosis of ovarian pregnancy) 1) the oviduct on the affected side must be intact; 2) the amnionic sac must occupy the position of the ovary; 3) the amnionic sac must be connected to the uterus by the ovarian ligament; and 4) ovarian tissue must be present in the wall of the amnionic sac.

Crithidia (kri-thid′e-a)
A genus of asexual, monogenetic, insect-parasitizing flagellates in the family Trypanosomatidae. [Mod. L., fr. G. krithidion, dim. of krithe, barley]

crithidia (kri-thid′e-a)
Former term for epimastigote. [Mod. L. fr. G. krithidion, dim. of krithe, barley]

critical (krit-i-kal)
1. Denoting or of the nature of a crisis. 2. Denoting a morbid condition in which death is possible. 3. In sufficient quantity as to constitute a turning point.

CRL
Abbreviation for crown-rump length.

CRM
Abbreviation for cross-reacting material.

CRM
Abbreviation for certified reference material.

C.R.N.A.
Abbreviation for certified registered nurse anesthetist.

cRNA
Abbreviation for complementary ribonucleic acid.

CRO
Abbreviation for cathode ray oscilloscope.

Crocq
Jean, Belgian physician, 1868–1925. See C. disease.

crocus (kro′kus)
The dried stigmas of C. sativus (C. of ficinalis) (family Iridaceae), formerly used occasionally in flatulent dyspepsia; also formerly used as an antispasmodic in asthma and dysmenorrhea and as a coloring and flavoring agent. SYN: saffron. [L. fr. G. krokos, the c., saffron (made from its stigmas)]

Crohn
Burrill B., U.S. gastroenterologist, 1884–1983. See C. disease.

cromolyn sodium (kro′mo-lin)
Used for the prevention of asthmatic attack. Stabilizes mast cell membranes to prevent the release of leukotrienes and other bronchospasm-inducing substances. SYN: sodium cromoglycate.

Cronkhite
Leonard W., Jr., U.S. physician, *1919. See C.-Canada syndrome.

Crooke
Arthur, English pathologist, *1905. See C. granules, under granule, C. hyaline change, C. hyaline degeneration.

Crookes
Sir William, British physicist and chemist, 1832–1919; winner of the Nobel Prize in chemistry in 1907. See C. glass, C.-Hittorf tube.

Crosby
William Holmes, Jr., U.S. physician, *1914. See C. capsule.

cross (kros)
1. Any figure in the shape of a c. formed by two intersecting lines. SYN: crux. 2. SYN: crux of heart. 3. A method of hybridization or the hybrid so produced. [F. croix, L. crux] back c. the mating between an animal that is homozygous at a locus of interest and an animal that is heterozygous, commonly from the same ancestral stock. double back c. a mating that is a back c. at each of two loci of interest; of special value and importance in linkage analysis. hair crosses [TA] crosslike figures formed by hairs growing from two directions that meet and then separate in a direction perpendicular to the original orientation. SYN: cruces pilorum [TA] . maltese c. a tetrad formation of the early ringlike parasites within the red blood cell seen in babesiosis. Ranvier crosses black or brown figures in the shape of a c., marking Ranvier nodes in the longitudinal section of a nerve stained with silver nitrate. test c. in experimental genetics, a deliberate mating designed to test claims about the pattern of inheritance of one or more traits.

crossbite (kros′bit)
An abnormal relation of one or more teeth of one arch to the opposing tooth or teeth of the other arch due to labial, buccal, or lingual deviation of tooth position, or to abnormal jaw position.

crossbreed (kros′bred)
1. SYN: hybrid. 2. To breed a hybrid.

crossbreeding (kros′bred-ing)
SYN: hybridization.

cross-dressing
Clothing oneself in the clothes of the opposite sex. See transvestism.

cross-eye (kros′i)
Alternative spelling for crossed eyes, under eye.

crossing-over, crossover (kros-ing-o′ver, kros′o-ver)
Reciprocal exchange of material between two paired chromosomes during meiosis, resulting in the transfer of a block of genes from each chromosome to its homologue. In contrast to genetic recombination (2), which is a phenotypic phenomenon, c. is genotypic. Any even number of crossing-overs between two loci will cancel out phenotypically and no recombination will occur. somatic crossing-over c. that occurs during the mitosis of somatic cells, in contrast to that which occurs in meiosis. uneven crossing-over, unequal crossing-over c. that happens when the breaks do not occur at precisely homologous points in two chromatid strands, and hence results in localized duplication of genetic material in one chromatid and complementary deletion in the other.

cross-link (kros-lingk)
A covalent linkage between two polymers or between two different regions of the same polymer.

cross-matching (kros′match-ing)
1. A test for incompatibility between donor and recipient blood, carried out prior to transfusion to avoid potentially lethal hemolytic reactions between the donor's red blood cells and antibodies in the recipient's plasma, or the reverse; performed by mixing a sample of red blood cells of the donor with plasma of the recipient (major crossmatch) and the red blood cells of the recipient with the plasma of the donor (minor crossmatch). Incompatibility is indicated by clumping of red blood cells and contraindicates use of the donor's blood. 2. In allotransplantation of solid organs ( e.g., kidney), a test for identification of antibody in the serum of potential allograft recipients which reacts directly with the lymphocytes or other cells of a potential allograft donor; presence of these antibodies usually, if not always, contraindicates the performance of the transplantation because virtually all such grafts will be subject to a hyperacute type of rejection.

crossover
Refers to the phenomenon of sound presented to one ear may be perceived in the other ear by passing around the head by air conduction or through the head by bone conduction.

cross-section
1. A transverse section through a structure. 2. The probability of an activation (5) by a nuclear reaction when a material is bombarded by neutrons, as in the production of radionuclides in a pile; unit: barn (10−24 cm2/atom).

cross-sectional
See synchronic.

cross-taper (kros ta′per)
A practice in pharmacotherapy of lowering the dose of one medication while simultaneously increasing the dose of another medication.

crossway (kros′wa)
The crossing of two nerve paths. sensory c. the postlenticular portion of the posterior limb of the internal capsule of the brain.

Crosti
A., 20th century Italian dermatologist. See Gianotti-C. syndrome.

crotalid (kro′ta-lid)
Any member of the snake family Crotalidae.

Crotalidae (kro-tal′i-de)
A family of New World vipers characterized by the presence of a heat-sensitive loreal pit between each eye and nostril, and folding, caniculated, long anterior fangs.

crotalin (krot′a-lin)
A protein in rattlesnake venom. [Crotalus, a genus of rattlesnakes]

crotalism (kro′tal-izm)
SYN: crotalaria poisoning.

Crotalus (krot′a-lus)
A genus of rattlesnakes (family Crotalidae) native to North America, having large fangs that are replaced periodically throughout life and a venom that is both neurotoxic and hemolytic. The largest species are the diamondbacks of the southern states (C. adamanteus) and western states (C. atrox); the smallest are the pigmy rattlers. [G. krotalon, a rattle, fr. krotos, a rattling noise]

crotamiton (kro-tam′i-ton)
A sarcopticide for topical use in scabies.

crotaphion (kro-taf′e-on)
The tip of the greater wing of the sphenoid bone; a point in craniometry. [G. krotaphos, the temple of the head]

crotonase (kro′ton-as)
SYN: enoyl-CoA hydratase.

croton oil (kro′ton)
A fixed oil expressed from the seeds of Croton tiglium (family Euphorbiaceae), an East Indian shrub; used as an irritant purgative, and externally as a counterirritant and vesicant.

crotonyl-ACP reductase (kro′to-nil)
SYN: enoyl-ACP reductase.

crotoxin (kro-tok′sin)
The toxin from the venom of the North American rattlesnake. [Crotalus + toxin]

crottle (krot′el)
SYN: cudbear.

croup (kroop)
1. Acute obstruction of upper airway in infants and children characterized by a barking cough with difficult and noisy respiration. 2. Laryngotracheobronchitis in infants and young children caused by parainfluenza viruses 1 and 2. [Scots, probably from A.S. kropan, to cry aloud]

croupous (kroo′p-us)
Relating to croup; marked by a fibrinous exudation.

croupy (kroo′pe)
Having the characteristics of croup, as a c. cough.

Crouzon
Octave, French physician, 1874–1938. See C. disease, C. syndrome.

Crow
R.S., British physician. See C.-Fukase syndrome.

crowding (krowd′ing)
A condition in which the teeth are crowded, assuming altered positions such as bunching, overlapping, displacement in various directions, torsiversion, etc.

Crowe
Samuel J., U.S. physician, 1883–1955. See C.-Davis mouth gag.

crown (krown) [TA]
1. Any structure, normal or pathologic, resembling or suggesting a c. or a wreath. 2. In dentistry, that part of a tooth that is covered with enamel, or an artificial substitute for that part. SYN: corona [TA] . [L. corona] anatomical c. SYN: c. of tooth. artificial c. a fixed restoration of the major part of the entire coronal part of a natural tooth; usually of gold, porcelain, or acrylic resin. bell-shaped c. the c. of a tooth that has an exaggerated occlusogingival contour; human deciduous molars typify the bell-shaped c.. ciliary c. SYN: corona ciliaris. clinical c. that part of the c. of a tooth visible in the oral cavity. SYN: corona clinica. c. of head SYN: corona capitis. jacket c. a hollow c. of acrylic resin, fused porcelain or cast gold, combinations of gold and acrylic or gold and porcelain; it fits over the prepared stump of the natural c.. radiate c. SYN: corona radiata. c. of tooth the portion of a tooth covered with enamel. SYN: anatomical c., corona dentis. c. of Venus papular lesions of secondary syphilis on the forehead near the hair margin.

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