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Medical Dictionary


microstethoscope (mi-kro-steth′o-skop)
A very small stethoscope that amplifies the sounds heard. SYN: microstethophone.

microstomia (mi-kro-sto′me-a)
Smallness of the oral aperture. [micro- + G. stoma, mouth]

microsurgery (mi-kro-ser′jer-e)
Surgical procedures performed under the magnification of a surgical microscope.

microsuture (mi-kro-soo′choor)
Tiny caliber suture material, often 9-0 or 10-0, with an attached needle of corresponding size, for use in microsurgery.

microsyringe (mi′kro-si-rinj′)
A hypodermic syringe that has a micrometer screw attached to the piston, whereby accurately measured minute quantities of fluid may be injected.

microthelia (mi-kro-the′le-a)
Smallness of the nipples. [micro- + G. thele, nipple]

microtia (mi-kro′she-a)
Smallness of the auricle of the ear with a blind or absent external auditory meatus. [micro- + G. ous, ear]

Microtinae (mi-krot′in-e)
The rodent subfamily comprising voles or lemmings.

microtine (mi′kro-ten)
Relating to voles or lemmings.

microtome (mi′kro-tom)
An instrument for making sections of biological tissue for examination under the microscope. SEE ALSO: ultramicrotome. SYN: histotome.

microtomy (mi-krot′o-me)
The making of thin sections of tissues for examination under the microscope. SYN: histotomy. [micro- + G. tome, incision]

microtonometer (mi′kro-to-nom′e-ter)
A small tonometer invented by Krogh, originally intended for animals but later adapted to humans, for determining the tensions of oxygen and carbon dioxide in arterial blood; it provides the means of bringing a small bubble of air into gaseous equilibrium with a sample of blood obtained by arterial puncture. [micro- + G. tonos, tone, + metron, measure]

Microtrombidium (mi′kro-trom-bid′e-um)
A genus of chigger or harvest mites that cause severe itching from the presence of the larval stage (chigger) in the skin. [micro- + Mod. L. trombidium, a timid one]

microtropia (mi-kro-tro′pe-a)
Strabismus of less than four degrees, associated with amblyopia, eccentric fixation, or anomalous retinal correspondence. [micro- + G. trope, a turn, turning]

microtubule (mi-kro-too′bul)
A hollow, cylindrical cytoplasmic element, 20–27 nm in diameter and of variable length, that occurs widely in the cytoskeleton, cilia, and flagella of cells; microtubules play a role in the maintenance of cell shape and increase in number during mitosis and meiosis, where they are related to movement of the chromosomes by the nuclear spindle. subpellicular m. a m. lying beneath the unit membrane (pellicle) of many protozoans, often as a palisade of longitudinally arranged fibrils connected by fine lateral bridges that support the external cell form; in certain sporozoan stages a fixed number of microtubules are found, extending longitudinally from the polar ring. SYN: subpellicular fibril.

microvesicle (mi-kro-ves′i-kl)
A fluid-filled space formed within the epidermis that is too small to be recognized as a blister.

microvillus, pl .microvilli (mi-kro-vil′us, -vil′i)
One of the minute projections of cell membranes greatly increasing surface area; microvilli form the striated or brush borders of certain cells.

Microviridae (mi-kro-vir′i-de)
A family of small, spherical, bacterial viruses with a genome of single-stranded DNA (MW 1.7 × 106).

microvolt (μV) (mi′kro-volt)
One-millionth of a volt.

microwaves (mi′kro-wavz)
That portion of the radio wave spectrum of shortest wavelength, including the region with wavelengths of 1 mm to 30 cm (1000–300,000 megacycles per second). SYN: microelectric waves.

microwelding (mi-kro-weld′ing)
A method of fastening or joining stainless steel sutures or such sutures to needles.

microxyphil (mi-krok′si-fil)
A multinuclear oxyphil leukocyte. [micro- + G. oxys, acid, + philos, fond]

microzoon (mi-kro-zo′on)
A microscopic form of the animal kingdom; a protozoon. [micro- + G. zoon, animal]

micrurgical (mi-krer′ji-kal)
Relating to procedures performed on minute structures under a microscope. [micro- + G. ergon, work]

miction (mik′shun)
SYN: urination.

micturate (mik′choo-rat)
SYN: urinate. [see micturition]

micturition (mik-choo-rish′un)
1. SYN: urination. 2. The desire to urinate. 3. Frequency of urination. [L. micturio, to desire to make water]

Abbreviation for minimal infecting dose.

Middle. [A.S. mid, midd]

midazolam hydrochloride
A short-acting injectable benzodiazepine central nervous system depressant used for preoperative sedation.

midbody (mid′bod′e)
A dense stalk of residual interzonal spindle fibers (microtubules) and actin-containing filaments that is formed during anaphase of mitosis and connects daughter cells during telophase; midbodies are frequently observed between spermatids. SYN: intermediate body of Flemming.

midbrain (mid′bran)

midcarpal (mid′kar-pal)
1. Relating to the central part of the carpus. 2. Denoting the articulation between the two rows of carpal bones. SYN: carpocarpal. SYN: mediocarpal, mesocarpal.

middle (mid′el)
Denoting an anatomical structure that is between two other similar structures or that is midway in position. SYN: medius.

midge (midj)
The smallest of the biting flies, in the genus Culicoides; swarms may attack humans and other animals; vectors of filarial infections. [O.E. mycg]

midgracile (mid-gras′il)
Denoting an occasional fissure dividing the gracile lobe of the cerebellum into two parts.

midgut (mid′gut)
1. The central portion of the digestive tube; the distal duodenum, small intestine, and proximal colon. 2. The portion of the embryonic gut tract between the foregut and the hindgut which originally is open to the yolk sac.

midmenstrual (mid′men′stroo-al)
Denoting the several days midway in time between two menstrual periods.

midoccipital (mid′ok-sip′i-tal)
Relating to the central portion of the occiput. SYN: medioccipital.

midpain (mid′pan)
SYN: intermenstrual pain (1) .

midplane (mid′plan)
SYN: pelvic plane of least dimensions.

midriff (mid′rif)
SYN: diaphragm (1) . [A.S. mid, middle, + hrif, belly]

midsection (mid′sek-shun)
A cut or section through the middle of an organ.

midsternum (mid′ster′num)
SYN: body of sternum.

midtarsal (mid′tar′sal)
Relating to the middle of the tarsus. SYN: mediotarsal, mesotarsal.

midwife (mid′wif)
A person qualified to practice midwifery, having specialized training in obstetrics and child care. [A.S. mid, with, + wif, wife]

midwifery (mid′wif′re, mid-wif′e-re)
Independent care of essentially normal, healthy women and infants by a midwife, antepartally, intrapartally, postpartally, and/or obstetrically in a hospital, birth center, or home setting, and including normal delivery of the infant, with medical consultation, collaborative management, and referral of cases in which abnormalities develop; strong emphasis is placed on educational preparation of parents for childbearing and childrearing, with an orientation toward childbirth as a normal physiological process requiring minimal intervention.

Johann F., Swiss pathologist, 1811–1887. See M. elastoma, M. granuloma, M. tubes, under tube.

Abbreviation for migration-inhibitory factor.

mifepristone (mif′pris-ton)
Synthetic chemical compound with antiprogesterone properties used for early pregnancy termination; the substance binds with glucocorticoid receptors resulting in increased adrenal gland secretion. SYN: RU-486.

migraine (mi′gran, mi-gran′)
A symptom complex occurring periodically and characterized by pain in the head (usually unilateral), vertigo, nausea and vomiting, photophobia, and scintillating appearances of light. Classified as classic m., common m., cluster headache, hemiplegic m., ophthalmoplegic m., and ophthalmic m.. SYN: bilious headache, blind headache, hemicrania (1) , sick headache, vascular headache. [through O. Fr., fr. G. hemi- krania, pain on one side of the head, fr. hemi-, half, + kranion, skull] abdominal m. 1. m. in children accompanied by paroxysmal abdominal pain. This must be distinguished from similar symptoms requiring surgical attention. 2. a disorder that causes intermittent abdominal pain and is believed to be related to m.; abdominal m. has some of the features of m., e.g., there may be a strong family history of m. headaches, and the condition may be relieved by sleep; however, a headache may not be present. The diagnosis depends on excluding other causes of abdominal pain. acephalgic m. a classic m. episode in which the teichopsia is not followed by a headache. SYN: m. without headache. basilar m. a m. accompanied by transient brainstem signs (vertigo, tinnitus, perioral numbness, diplopia, etc.) thought to be due to vasospastic narrowing of the basilar artery. classic m. a form of hemicrania m. preceded by a scintillating scotoma (teichopsia). common m. a form of m. headache without the visual prodrome, that is not limited on one side of the head but nevertheless is recognizable as m. because of the stereotyped course; the tendency to nausea, photophobia, and phonophobia; and the relief produced by sleep. complicated m. a m. attack during which an infarction of tissue takes place. fulgurating m. m. characterized by its abrupt commencement and the severity of the episode. Harris m. SYN: periodic migrainous neuralgia. hemiplegic m. a form associated with transient hemiplegia. ocular m. a form of m. with transient monocular vision loss, typically in young adults, that may or may not be associated with headache around the eye. SYN: retinal m.. ophthalmoplegic m. a form of m. associated with paralysis of the extraocular muscles. retinal m. SYN: ocular m.. m. without headache SYN: acephalgic m..

migration (mi-gra′shun)
1. Passing from one part to another, said of certain morbid processes or symptoms. 2. SYN: diapedesis. 3. Movement of a tooth or teeth out of normal position. 4. Movement of molecules during electrophoresis, centrifugation, or diffusion. [L. migro, pp. -atus, to move from place to place] branch m. a process in which the cross connection around the position where two DNA helices are joined moves along the strands. epithelial m. apical shift of epithelial attachment, exposing more of the tooth crown. m. of ovum the transperitoneal passage of an ovum from the ovarian follicle into the uterine tube.

Abbreviation for melanotropin release-inhibiting hormone.

Victor G., U.S. radiologist, *1919. See Wilson-M. syndrome.

Johannes von-Radecki, Polish surgeon in Germany, 1850–1905. See M. aphthae, under aphtha, M. cells, under cell, M. clamp, M. disease, M. drain, M. operation, M. syndrome, M.-Vladimiroff amputation, Vladimiroff-M. amputation, Heineke-M. pyloroplasty.

William E., British surgeon, 1869–1947. See M. operation.

milia (mil′e-a)
Plural of milium.

miliaria (mil-e-a′re-a)
An eruption of minute vesicles and papules due to retention of fluid at the orifices of sweat glands. SYN: miliary fever (2) . [L. miliarius, relating to millet, fr. milium, millet] m. alba m. with vesicles containing a milky fluid. apocrine m. SYN: Fox-Fordyce disease. m. crystallina a noninflammatory form of m. in which the fragile subcorneal vesicles, about 100 mm in diameter, are filled with clear fluid. SYN: crystal rash, sudamina (2) . m. profunda pale firm papules, most commonly on the trunk; m. profunda is asymptomatic and results from severe damage to the sweat ducts after repeated episodes of m. rubra. Heat stress may cause collapse because of the high proportion of nonfunctional sweat glands. m. rubra an eruption of pruritic macules with small central vesicles at the orifices of sweat glands, accompanied by redness and inflammatory reaction of the skin. SYN: heat rash, prickly heat, summer rash, wildfire rash.

miliary (mil′e-a-re, mil′ya-re)
1. Resembling a millet seed in size (about 2 mm). 2. Marked by the presence of nodules of millet seed size on any surface. [see miliaria]

milieu (mel-u′)
1. Surroundings; environment. 2. In psychiatry, the social setting of the mental patient, e.g., the family setting or a hospital unit. [Fr. mi, fr. L. medius, middle, + lieu, fr. L. locus, place] m. intérieur, m. interne the internal environment; the fluids bathing the tissue cells of multicellular animals.

military antishock trousers (MAST)
SYN: pneumatic antishock garment.

milium, pl .milia (mil′e-um, -e-a)
A tiny subepidermal keratinous cyst, usually multiple and therefore commonly referred to in the plural. M. may be primary (developmental), occurring predominantly on the face in infants and adults, or retention cysts secondary to causes of scarring or subepidermal blisters involving adnexal epithelium. SYN: whitehead (1) . [L. millet]

1. A white liquid, containing proteins, sugar, and lipids, secreted by the mammary glands, and designed for the nourishment of the young. SYN: lac (1) . 2. Any whitish milky fluid; e.g., the juice of the coconut or a suspension of various metallic oxides. 3. A pharmacopeial preparation that is a suspension of insoluble drugs in a water medium; distinguished from gels mainly in that the suspended particles of m. are larger. 4. SYN: strip (1) . [A.S. meolc] acidophilus m. m. inoculated with a culture of Bacillus acidophilus. m. of bismuth a suspension of bismuth hydroxide and bismuth subcarbonate in water; used in gastrointestinal disorders as a protective agent. buddeized m. Budde process. certified m. cow's m. that does not have more than the maximal permissible limit of 10,000 bacteria per ml at any time prior to delivery to the consumer, and that must be cooled to 10°C or less and maintained at that temperature until delivery. certified pasteurized m. cow's m. in which the maximum permissible limit for bacteria should not be more than 10,000 bacteria per ml before pasteurization and not more than 500 bacteria per ml after pasteurization; it must be cooled to 7.2°C or less and maintained at that temperature until delivery. condensed m. a thick liquid prepared by the partial evaporation of cow's m., with or without the addition of sugar. fortified m. m. to which some essential nutrient, usually vitamin D, has been added. fortified vitamin D m. m. produced through direct addition of vitamin D; standardized at 400 USP units per quart. irradiated vitamin D m. cow's m. exposed in a thin film to ultraviolet light and standardized to contain 400 USP units of vitamin D per quart. lactobacillary m. m. inoculated with a culture of Bacillus acidophilus, B. bulgaricus, or other lactic acid-forming microorganism. m. of magnesia mixture of magnesium hydroxide; an aqueous solution of magnesium hydroxide, used as an antacid and laxative. SYN: magnesia magma. metabolized vitamin D m. m. produced by feeding irradiated yeast to cows; standardized to contain not less than 400 USP units per quart. modified m. cow's m. altered, by increasing the fat and reducing the amount of protein, to resemble human m. in composition. perhydrase m. m. treated by the addition of hydrogen peroxide. See Budde process. skim m., skimmed m. the aqueous (noncream) part of m. from which casein is isolated. m. of sulfur SYN: precipitated sulfur. vitamin D m. cow's m. to which vitamin D has been added, to contain 400 USP units of vitamin D per quart. witch's m. a secretion of colostrum-like m. sometimes occurring in the glands of newborn infants of either sex 3 to 4 days after birth and lasting a week or two; due to endocrine stimulation from the mother before birth.

Louis A., U.S. roentgenologist, 1895–1951. See M. syndrome.

milkpox (milk′poks)
SYN: alastrim.

Auguste L.J., French physician, 1830–1915. See M.-Gubler syndrome.

Thomas Grier, U.S. physician, *1886. See M.-Abbott tube.

Willoughby D., U.S. dentist, 1853–1907. See M. chemicoparasitic theory.

millet seed (mil′et)
The seed of a grass, formerly used as a rough designation of size of about 2 mm in diameter.

milli- (m)
Prefix used in the SI and metric system to signify submultiples of one-thousandth (10−3). [L. mille, one thousand]

milliampere (ma, mA) (mil′e-am′per)
One thousandth of an ampere.


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