Dorlands Word Of The Day

Front 1

hydrocephalus ex vacuo

Back 1

a compensatory replacement by cerebrospinal fluid of the volume of tissue lost in atrophy of the brain.

Front 2

Ixodes pacificus

Back 2

a common deer and cattle tick of California, which may bite humans; it is the vector of Lyme disease in the western United States and is a possible vector of tularemia.

Front 3

pellagra

Back 3

a clinical deficiency syndrome due to deficiency of niacin (or failure to convert tryptophan to niacin) and characterized by dermatitis, inflammation of mucous membranes, diarrhea, and psychic disturbances. The dermatitis occurs on the portions of the body exposed to light or trauma. Mental symptoms include depression, irritability, anxiety, confusion, disorientation, delusions, and hallucinations.

Front 4

diamond-shaped murmur

Back 4

a cardiac murmur with a characteristic crescendo-decrescendo pattern of intensity on the phonocardiogram; it is almost always a systolic ejection murmur caused by aortic stenosis.

Front 5

second-degree burn

Back 5

a burn that affects the epidermis and the dermis, classified as superficial or deep according to the depth of injury. The superficial type involves the epidermis and the papillary dermis and is characterized by pain, edema, and the formation of blisters; it heals without scarring. The deep type extends into the reticular dermis, is pale and anesthetic, and results in scarring. Called also partial thickness burn.

Front 6

supraoccipital bone

Back 6

a bone developing from a separate ossification center in the fetus, which becomes the squamous part of the occipital bone below the superior nuchal line.

Front 7

polarity therapy

Back 7

a bodywork technique that combines tissue manipulation with theories of vital energy derived from ayurveda and acupuncture. It is believed that energy blockages within the body result in imbalances, which in turn manifest as pain. Manipulation, using light touch and medium and deep pressure, is used to release these energy blockages and restore balance. Exercise and nutritional and lifestyle counseling may also be included in the therapy.

Front 8

osteochondroma

Back 8

a benign tumor consisting of projecting adult bone capped by cartilage projecting from the lateral contours of endochondral bones. Called also chondrosteoma, osteocartilaginous exostosis, and osteoenchondroma.

Front 9

coal macule

Back 9

a dark spot seen on the lung in coal workers' pneumoconiosis, representing an aggregation of dust, dust-filled macrophages, and fibroblasts.

Front 10

Pel-Ebstein fever

Back 10

a cyclic fever occasionally seen in Hodgkin's disease or certain other diseases, characterized by irregular episodes of pyrexia of several days' duration, with intervening afebrile periods lasting for days or weeks. Called also Murchison-Pel-Ebstein fever and Pel-Ebstein pyrexia.

Front 11

second somatosensory area, secondary somatosensory area

Back 11

a cortical projection area that receives somatic sensations mainly from the skin, particularly sensations of pain and of movement across the skin. Called also SII area.

Front 12

fraise

Back 12

a conical or hemispherical bur for cutting osteoplastic flaps or enlarging trephine openings.

Front 13

exudative retinopathy

Back 13

a condition marked by masses of white or yellowish exudate in the posterior part of the ocular fundus, with deposit of cholesterin and blood debris from retinal hemorrhage, and leading to destruction of the macula and blindness. Called also exudative retinitis and Coats' disease or retinitis.

Front 14

pellagra

Back 14

a clinical deficiency syndrome due to deficiency of niacin (or failure to convert tryptophan to niacin) and characterized by dermatitis, inflammation of mucous membranes, diarrhea, and psychic disturbances. The dermatitis occurs on the portions of the body exposed to light or trauma. Mental symptoms include depression, irritability, anxiety, confusion, disorientation, delusions, and hallucinations.

Front 15

Pel-Ebstein fever

Back 15

a cyclic fever occasionally seen in Hodgkin's disease or certain other diseases, characterized by irregular episodes of pyrexia of several days' duration, with intervening afebrile periods lasting for days or weeks. Called also Murchison-Pel-Ebstein fever and Pel-Ebstein pyrexia.

Front 16

retrovascular hernia

Back 16

a femoral hernia that passes within the femoral sheath but exits posterior to the femoral vessels; called also Serafini's hernia.

Front 17

polymeria

Back 17

a developmental anomaly characterized by the presence of supernumerary parts or organs of the body.

Front 18

micromelia

Back 18

a developmental anomaly characterized by abnormal smallness or shortness of the limbs.

Front 19

second somatosensory area, secondary somatosensory area

Back 19

a cortical projection area that receives somatic sensations mainly from the skin, particularly sensations of pain and of movement across the skin. Called also SII area.

Front 20

external elastic membrane

Back 20

a fenestrated elastic membrane that constitutes the innermost component of the tunica adventitia of arteries. Called also external elastic lamina.

Front 21

endrin

Back 21

a highly toxic chlorinated hydrocarbon insecticide; if ingested or absorbed through the skin by a human or other animal, it can cause potentially fatal neurotoxicity such as tremors and convulsions.

Front 22

enteroendocrine cells

Back 22

a group of APUD cells (amine precursor uptake and decarboxylation cells, which concentrate the amino acid precursors of certain amines and decarboxylate them to form amines that function as regulators and neurotransmitters), which may be divided into a number of populations on the basis of polypeptide hormone and biogenic amine production, found scattered throughout the gastrointestinal epithelium, mainly at the base of the epithelium; their numerous small secretory granules are concentrated chiefly between the nucleus and the cell base. Their secretions affect gastrointestinal motility, pancreatic and biliary secretions, and gastrointestinal epithelial growth, as well as being regulators of other enteroendocrine products. Called also basal granular cells and endocrine cells of the gut.

Front 23

Omphalia

Back 23

a genus of mushrooms of the family Agaricaceae. O. lapidescens is dried and used as an anthelmintic called raigan in Chinese medicine.

Front 24

smooth-rough variation, S-R variation

Back 24

a genetic mutation or an adaptation seen in bacteria, most often evidenced by a change in the surface of colonies from smooth (S, glossy) to rough (R, dull). The change correlates with pathogenicity, S strains being generally more virulent and R strains less so. The cells in S colonies have polysaccharide capsules and are more antigenically complete; R cells contain little or no capsule. The term may also refer to changes in other cell structures such as flagella and somatic antigens, as well as susceptibility to bacteriophage. Variations are often reversible and tend to result in mixed types on repeated subculture.

Front 25

cavernous rale

Back 25

a hollow and metallic rale caused by the alternate expansion and contraction of a pulmonary cavity during respiration.

Front 26

funiculus cuneatus lateralis

Back 26

a longitudinal ridge on the medulla oblongata between the line of roots of the spinal accessory nerve and the fasciculus cuneatus.

Front 27

iseikonic lens

Back 27

a lens that magnifies but does not refract; it is used to treat aniseikonia (a condition in which the ocular image of an object as seen by one eye differs in size and shape from that seen by the other) because it changes the sizes of the images on the retinas of the eyes. Called also aniseikonic lens and size lens.

Front 28

intermediate host

Back 28

a host in which a parasite passes one or more of its asexual (larval) stages; usually designated first and second, if there is more than one.

Front 29

pulmonary ventilation

Back 29

a measure of the rate of ventilation, referring to the total exchange of air between the lungs and the ambient air, usually in liters per minute.

Front 30

titanium dioxide pneumoconiosis

Back 30

a mild form of pneumoconiosis seen in workers inhaling excessive amounts of titanium dioxide dust.

Front 31

hydroxyethyl cellulose

Back 31

a partially substituted, nonionic, water-soluble cellulose ether available in several grades that vary in viscosity and degree of substitution and some of which are modified to improve their dispersion in water; it may contain suitable anticaking agents. Used as a pharmaceutic aid (suspending agent and viscosity-increasing agent).

Front 32

cotyloid foramen

Back 32

a passage between the margin of the acetabulum and the transverse ligament.

Front 33

diagnostic cast

Back 33

a positive reproduction of the maxillary and/or mandibular arches, usually made from gypsum, and used for study and treatment planning. Called also preextraction cast, preoperative cast, and study cast.

Front 34

subocclusal surface

Back 34

a portion of the surface of a tooth that is directed toward but does not make contact with the occlusal surface of its opposite number in the other jaw.

Front 35

Bombay phenotype

Back 35

a rare blood phenotype produced by the interaction of genes of the ABO blood group and a rare recessive gene at a different locus, resulting in a complete lack of H antigen; cells of individuals with this phenotype lack A, B, and H antigens, and their serum contains anti-A, anti-B, and anti-H antibodies.

Front 36

canine eminence

Back 36

a prominent bony ridge overlying the root of either canine tooth on the labial surface of both the maxilla and the mandible.

Front 37

oral tuberculosis

Back 37

a rare condition usually occurring as a bloodborne complication of pulmonary tuberculosis, most often involving the gingivae and tongue, and characterized by the presence of small, crateriform, painless ulcers that bleed readily and are surrounded by edema or reddish nodules.

Front 38

tritanopia

Back 38

a rare type of dichromatic vision characterized by retention of the sensory mechanism for two hues only (red and green) of the normal 4-primary quota, and lacking blue and yellow, with loss of luminance and shift of brightness and hue curves toward the long-wave end of the spectrum. Often associated with drug administration, retinal detachment, or diseases of the nervous system.

Front 39

porokeratosis

Back 39

a rare, chronic, progressive autosomal dominant skin disorder, seen most often in males, usually first appearing in early childhood, and characterized clinically by the presence of crater-like patches with central atrophy and an elevated thick keratotic border that enlarge to form circinate, serpiginous, or gyrate lesions, and histologically by a cornoid lamella. Called also porokeratosis of Mibelli.

Front 40

nucleus pulposus disci intervertebralis, pulpy nucleus of intervertebral disk

Back 40

a semifluid mass of fine white and elastic fibers that forms the central portion of an intervertebral disk; it has been regarded as the persistent remains of the embryonic notochord.

Front 41

penicillin V

Back 41

a semisynthetic oral penicillin prepared from cultures of the mold Penicillium in the presence of 2-phenoxyethanol with an autolysate of yeast as the source of nitrogen. It is a broad-spectrum antibiotic having pharmacologic and toxic properties similar to those of other penicillins, and is less potent than penicillin G. Called also phenoxymethyl p.

Front 42

Adie's syndrome

Back 42

a syndrome consisting of a pathological pupil reaction (tonic pupil), the most important element of which is a myotonic condition on accommodation; the pupil on the affected side contracts on near vision more slowly than does the pupil on the opposite side, and it also dilates more slowly. The affected pupil does not usually react to direct or indirect light, but it may do so in an abnormal fashion. Certain tendon reflexes are absent or diminished, usually the patellar reflexes, but there are no motor or sensory disturbances, nor demonstrable changes indicative of disease of the nervous system. Called also Holmes-Adie syndrome.

Front 43

velum transversum

Back 43

a transverse fold of the tela choroidea marking the boundary between the diencephalon and the telencephalon in the embryonic brain.

Front 44

primed lymphocyte typing (PLT)

Back 44

a technique used for typing of Class II HLA antigens: unknown cells are exposed to a panel of lymphocytes primed against specific HLA antigens by prior coculture with stimulator cells that matched the primed cells at all but one HLA locus; when restimulated by the same HLA antigen the primed cells give a secondary proliferative response, which shows that the unknown cells bear the same antigen as the stimulator cells.

Front 45

suprascapular neuropathy

Back 45

a type of entrapment neuropathy (injury of a peripheral nerve by compression in its course through a fibrous or osseofibrous tunnel or at a point where it abruptly changes its course through deep fascia over a fibrous or muscular band) caused by a lesion of the suprascapular nerve at the scapular notch, characterized by pain and weakness at the shoulder joint upon external rotation of the upper arm.

Front 46

scrofuloderma

Back 46

a tuberculous or nontuberculous mycobacterial infection affecting children and young adults, representing direct extension of tuberculosis into the skin from underlying structures such as lymph nodes (especially the cervical), bone or lung or by contact exposure to tuberculosis. It is manifested by the development of painless subcutaneous swellings that evolve into cold abscesses, multiple ulcers, and draining sinus tracts. Called also tuberculosis colliquativa and tuberculosis colliquativa cutis.

Front 47

Listing's plane

Back 47

a transverse vertical plane perpendicular to the anteroposterior axis of the eye, and containing the center of motion of the eyes; in it lie the transverse and vertical axes of ocular rotation.

Front 48

hepatitis E

Back 48

a type of viral hepatitis caused by exposure to hepatitis E virus, transmitted by the fecal-oral route, usually via contaminated water. Chronic infection does not occur, but acute hepatitis may be fatal in pregnant women. Called also enterically transmitted non-A, non-B hepatitis.

Front 49

arteriosclerotic nephritis

Back 49

a type of nephritis resulting either from the aging process, with hyaline changes of the large and small arterioles, or from hypertension, with hyaline or muscular changes of the small arterioles in the glomerular hilum. Renal damage occurs primarily through ischemic atrophy of the tubules with resultant focal or diffuse fibrosis of interstitial tissue.

Front 50

hypothymia

Back 50

abnormal diminution of emotional tone, as in depression.

Front 51

lactase

Back 51

an enzyme occurring in the brush border membrane of the intestinal mucosa; together with glycosylceramidase (phlorizin hydrolase), it forms the ?-glycosidase complex. The enzyme catalyzes the hydrolytic cleavage of lactose to galactose and glucose and also cleaves terminal nonreducing galactose residues from ?-glycosides with large hydrophilic aglycons. Reduced or absent enzyme activity (lactase deficiency) may result in symptoms of lactose intolerance.

Front 52

acute promyelocytic leukemia

Back 52

acute myelogenous leukemia in which more than half the cells are malignant promyelocytes, often associated with abnormal bleeding secondary to thrombocytopenia, hypofibrinogenemia, and decreased levels of coagulation factor V; it usually occurs in young adults. Called also promyelocytic leukemia.

Front 53

adhesive atelectasis

Back 53

alveolar collapse with patent airways, often related to absence or inactivation of surfactant, such as in respiratory distress syndrome of newborn or radiation pneumonitis.

Front 54

acute promyelocytic leukemia

Back 54

acute myelogenous leukemia in which more than half the cells are malignant promyelocytes, often associated with abnormal bleeding secondary to thrombocytopenia, hypofibrinogenemia, and decreased levels of coagulation factor V; it usually occurs in young adults. Called also promyelocytic leukemia.

Front 55

obesity index

Back 55

body weight divided by body volume.

Front 56

recessional lines

Back 56

lines or markings on the teeth due to the recession, in the formative period of the teeth, of the soft tissue which gives place to the dentin.

Front 57

linea mammillaris

Back 57

mammillary line: an imaginary vertical line on the anterior surface of the body, passing through the center of the nipple.