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Medical Dictionary


masticate (mas′ti-kat)
To chew; to perform mastication.

mastication (mas-ti-ka′shun)
The process of chewing food in preparation for deglutition and digestion; the act of grinding or comminuting with the teeth. [L. mastico, pp. -atus, to chew]

masticatory (mas′ti-ka-to-re)
Relating to mastication.

mastich, mastiche (mas′tik, mas′ti-ke)
SYN: mastic.

Mastigophora (mas′ti-gof′o-ra)
The flagellates, a subphylum of Protozoa having one or more locomotory flagella, a single vesicular nucleus, and symmetric binary fission; sexual reproduction is unknown in many groups ( e.g., Volvox, Trypanosoma, Euglena). It consists of two classes: Phytomastigophorea (to which Euglena belongs), which contains chlorophyll and is therefore photosynthetic and holophytic (although this has secondarily been lost in some groups), and Zoomastigophorea (including Trypanosoma and Leishmania), which lacks chromatophores and is heterotrophic. [G. mastix (mastig-), a whip, + phoros, bearing]

mastigote (mas′ti-got)
An individual flagellate. [G. mastix, a whip]

mastitis (mas-ti′tis)
Inflammation of the breast. SYN: mastadenitis. [masto- + G. -itis, inflammation] chronic cystic m. older term corresponding to fibrocystic condition of the breast. gargantuan m. obsolete term for chronic inflammation of the breast with great enlargement of the gland. glandular m. SYN: parenchymatous m.. granulomatous m. a rare granulomatous inflammation of lobular breast tissue, with multinucleated giant cells; sarcoidosis is excluded by the frequent presence of neutrophils and absence of involvement of other tissues. interstitial m. inflammation of the connective tissue of the mammary gland. lactational m. SYN: puerperal m.. m. neonatorum m. in the secreting breast tissue of the newborn, usually staphylococcal. parenchymatous m. inflammation of the secreting tissue of the breast. SYN: glandular m.. plasma cell m. a condition of the breasts characterized by tumorlike indurated masses containing numerous plasma cells, usually resulting from mammary duct ectasia; although clinically resembling malignant disease (attachment to skin and enlargement of axillary lymph nodes), it is not neoplastic. puerperal m. m., usually suppurative, occurring in the later part of the puerperium. SYN: lactational m.. retromammary m. SYN: submammary m.. stagnation m. painful distention of the breast occurring during the latter days of pregnancy and the first days of lactation. submammary m. inflammation of the tissues lying deep to the mammary gland. SYN: retromammary m.. suppurative m. inflammation of the breast due to infection with pyogenic bacteria.

masto-, mast-
The breast; the mastoid. Cf.:mammo-, mazo-. [G. mastos]

mastoccipital (mast′ok-sip′-i-tal)
SYN: masto-occipital.

mastocyte (mas′to-sit)
SYN: mast cell.

mastocytogenesis (mas′to-si′to-jen′e-sis)
Formation and development of mast cells. [mastocyte + G. genesis production]

mastocytoma (mas′to-si-to′ma)
A fairly well-circumscribed accumulation or nodular focus of mast cells, grossly resembling a neoplasm. [mastocyte + G. -oma, tumor]

mastocytosis (mas′to-si-to′sis)
Abnormal proliferation of mast cells in a variety of tissues; may be systemic, involving a variety of organs, or cutaneous (urticaria pigmentosa). [mastocyte + G. -osis, condition] diffuse m. infiltration of many organ systems by mast cells with varied clinical manifestations that can include fever, weight loss, flushing, bronchospasm, rhinorrhea, palpitations, dyspnea, diarrhea, gastrointestinal bleeding, and hypotension. SYN: systemic m.. diffuse cutaneous m. a benign process consisting of focal cutaneous infiltrates composed of mast cells; lesions are flat or slightly elevated, form wheals and itch when stroked; bone lesions may occur. systemic m. SYN: diffuse m..

mastodynia (mas-to-din′e-a)
Pain in the breast. SEE ALSO: mammary neuralgia. SYN: mammalgia, mastalgia. [masto- + G. odyne, pain]

mastoid (mas′toyd)
1. Resembling a mamma; breast-shaped. 2. Relating to the m. process, antrum, cells, etc. SYN: mastoidal. [masto- + G. eidos, resemblance]

mastoidal (mas-toy′dal)
SYN: mastoid (2) .

mastoidale (mas-toy-da′le)
The lowest point on the contour of the mastoid process.

mastoidectomy (mas′toy-dek′to-me)
A group of operations on the mastoid process of the temporal bone and middle ear to drain, expose, or remove an infectious, inflammatory, or neoplastic lesion. [mastoid (process) + G. ektome, excision] complete m. an operation to exenterate the air cell system from the mastoid process of the temporal bone for the drainage of the suppuration in acute mastoiditis. SYN: simple m.. modified radical m. an operation for the management of cholesteatoma that lies lateral to the remnant of the tympanic membrane and middle-ear ossicles; involves exenteration of the remaining air cells of the mastoid process and removal of the posterior and superior walls of the external auditory canal to open the mastoid and attic of the middle ear to the outside and preserve hearing. radical m. an operation for the management of extensive cholesteatoma; involves exenteration of the remaining mastoid air cells and removal of the posterior and superior walls of the external auditory canal and the remnants of the tympanic membrane and middle-ear ossicles to exteriorize the mastoid cavity and middle ear through the external auditory canal. SYN: tympanomastoidectomy. simple m. SYN: complete m..

mastoiditis (mas-toy-di′tis)
Inflammation of any part of the mastoid process. SYN: mastoid empyema. sclerosing m. a chronic m. in which the trabeculae are greatly thickened, tending to obliterate the cells.

mastoncus (mas-tong′kus)
A tumor or swelling of the breasts. [masto- + G. onkos, mass]

masto-occipital (mas′to-ok-sip′i-tal)
Relating to the mastoid portion of the temporal bone and to the occipital bone, denoting the suture uniting them. SYN: mastoccipital.

mastoparietal (mas′to-pa-ri′e-tal)
Relating to the mastoid portion of the temporal bone and to the parietal bone, denoting the suture uniting them.

mastopathy (mas-top′a-the)
Any disease of the breasts. [masto- + G. pathos, suffering]

mastopexy (mas′to-pek-se)
Plastic surgery to elevate a ptotic breast in normal position, often with some improvement in shape. [masto- + G. pexis, fixation]

mastoplasia (mas-to-pla′ze-a)
Enlargement of the breast. [masto- + G. plasis, a molding]

mastoplasty (mas′to-plas-te)
SYN: mammaplasty. [masto- + G. plastos, formed]

mastoptosis (mas-top-to′sis)
Ptosis or sagging of the breast. [masto- + G. ptosis, a falling]

mastorrhagia (mas-to-ra′je-a)
Hemorrhage from a breast. [masto- + G. rhegnymi, to burst forth]

mastosquamous (mas′to-skwa′mus)
Relating to the mastoid and the squamous portions of the temporal bone.

mastosyrinx (mas′to-sir′ingks)
A fistula of the mammary gland. [masto- + G. syrinx, tube]

mastotomy (mas-tot′o-me)
Incision of the breast. SYN: mammotomy. [masto- + G. tome, incision]

masturbate (mas′ter-bat)
To practice masturbation. [L. masturbari, pp. masturbatus]

masturbation (mas′ter-ba′shung)
Self-stimulation of the genitals for erotic pleasure, often resulting in orgasm.

Abbreviation for multifocal atrial tachycardia.

Rudolph, U.S. surgeon, 1860–1957.

The process of making a study group and a comparison group in an epidemiological study comparable with respect to extraneous or confounding factors such as age, sex, weight. impedance m. the force delivered through the mechanical advantages of the tympanic ossicles and the area ratio of the tympanic membrane to the oval window to overcome the acoustic impedance between the ambient air and the fluid in the inner ear.

maté (mah-ta′)
The dried leaves of Ilex paraguayensis and other species of Ilex (family Aquifoliaceae), shrubs growing in Paraguay and Brazil, which contain caffeine and tannin; used in South American countries as a beverage and medicinally as a diuretic and diaphoretic, and for the relief of headache. SYN: Paraguay tea. [Sp. maté, a vessel in which the leaves are prepared]

mater (ma′ter)
The “sheltering” coverings of the central nervous system. See arachnoid m., dura m., pia m.. [L. mother] arachnoidea m. cranialis [TA] SYN: cranial arachnoid m.. arachnoidea m. encephali cranial arachnoid m.. cranial pia m. [TA] the pia m. found specifically around the brain; contiguous with the arachnoid m. via the arachnoid trabeculae. SEE ALSO: pia m.. SYN: pia m. encephali&star. pia m. encephali cranial pia m.. pia m. spinalis [TA] SYN: spinal pia m.. SEE ALSO: pia m.. spinal arachnoid m. [TA] See spinal arachnoid m.. SEE ALSO: arachnoid m.. spinal pia m. [TA] the pia m. found specifically around the spinal cord; includes specializations such as the denticulate ligaments. SEE ALSO: pia m.. SYN: pia m. spinalis [TA] .

materia (ma-te′re-a)
Substance or matter. [L. substance] m. alba accumulation or aggregation of microorganisms, desquamated epithelial cells, blood cells and food debris loosely adherent to surfaces of plaques, teeth, gingiva or dental appliances. [L. white matter] m. medica 1. that aspect of medical science concerned with the origin and preparation of drugs, their doses, and their mode of administration; 2. any agent used therapeutically. SEE ALSO: pharmacognosy, pharmacology. [L. medical matter]

material (ma-ter′e-al)
That of which something is made or composed; the constituent element of a substance. [L. materialis, fr. materia, substance] base m. any substance from which a denture base may be made, such as shellac, acrylic resin, vulcanite, polystyrene, metal, etc. by-product m. radioactive m. produced by nuclear fission or by neutron irradiation in a nuclear reactor or similar device. certified reference m. (CRM) a reference m. documented by or traceable to a certificate or publication from a reputable source and that states the values of the properties concerned. contrast m. SYN: contrast medium. cross-reacting m. (CRM) a substance sufficiently different from a reference substance (R) to have a perceptibly different function from R, but similar enough to react with anti-R antibodies. dental m. any m. used in dentistry. genetic m. the carrier of hereditary information; in higher organisms it is duplex DNA. impression m. any substance or combination of substances used for making a negative reproduction or impression. plastic restoration m. in dentistry, any m. that may be shaped directly to the tooth cavity, such as amalgam, cement, or resin. restorative dental materials materials used to replace oral tissues in dentistry; e.g., amalgam, gold alloys, cements, porcelain, plastics, and denture materials.

materies morbi (ma-te′re-ez mor′bi)
The substance acting as the immediate cause of a disease. [L. the matter of disease]

maternal (ma-ter′nal)
Relating to or derived from the mother. [L. maternus, fr. mater, mother]

maternity (ma-ter′ni-te)
Motherhood. [see maternal]

mating (mat′ing)
The pairing of male and female for the purpose of reproduction. assortative m. selection of a mate with preference for (or aversion to) a particular genotype, i.e., nonrandom m.. SYN: nonrandom m.. cross m. cross. nonrandom m. SYN: assortative m.. random m. a practice of m. in which any egg has an equal opportunity of being fertilized by any sperm; thus the chance of one genotype at a particular locus combining with another genotype at that locus is random. SYN: panmixis.

matrass (mat′ras)
A long-necked glass vessel used for heating dry substances in chemical manipulations. [Fr. matras]

matrical (mat′ri-kal)
Relating to any matrix. SYN: matricial.

matricaria (mat-ri-ka′re-a)
The flowers of M. chamomilla (family Compositae); used internally as a tonic and externally as a counterirritant. SEE ALSO: chamomile. [L. matrix, womb]

matrices (ma′tri-sez, mat′ri-sez)
Plural of matrix. [L.]

matricial (ma-trish′al)
SYN: matrical.

matricide (mat′ri-sid)
1. The killing of one's mother. Cf.:patricide. 2. One who commits such an act. [L. mater, mother, + caedo, to kill]

matrilineal (mat-ri-lin′e-al)
Denoting descent through the female line. [L. mater, mother, + linea, line]

matrix, pl .matrices (ma′triks, mat′riks; ma′tri-sez, mat′ri-sez)
1. [NA] The formative portion of a tooth or a nail. 2. The intercellular substance of a tissue. 3. A surrounding substance within which something is contained or embedded, e.g., the fatty tissue in which blood vessels or lymph nodes lie; provides a m. for these embedded structures. 4. A mold in which anything is cast or swaged; a counterdie; a specially shaped instrument, plastic material, or metal strip used for holding and shaping the material used in filling a tooth cavity. 5. A rectangular array of numbers or symbol quantities that simplify the execution of linear operations of tedious complexity, e.g., the ITO method; the theory of matrices is widely used in solving simultaneous equations and in population genetics. [L. womb; female breeding animal] amalgam m. a device used during placement of the amalgam mass within a compound cavity preparation, facilitating proper condensation and contour thereof by providing a confining wall. bone m. the intercellular substance of bone tissue consisting of collagen fibers, ground substance, and inorganic bone salts. cartilage m. the intercellular substance of cartilage consisting of fibers and ground substance. cell m. SYN: cytoplasmic m.. cytoplasmic m. a fluid cytoplasmic substance filling the interstices of the cytoskeleton. SYN: cell m., cytomatrix. external m. the substance occupying the space between the inner and outer membrane of any organelle ( E.G., mitochondria) with a double membrane. identity m. a square m. in which the quantities on the diagnonal from top left to bottom right are all equal to 1 and all the other entries are 0. mitochondrial m. SYN: m. mitochondrialis. m. mitochondrialis the substance occupying the space enclosed by the inner membrane of a mitochondrion; it contains enzymes, filaments of DNA, ribosomes, granules, and inclusions of protein crystals, glycogen, and lipid. SYN: mitochondrial m.. nail m. [TA] the area of the corium on which the nail rests; it is extremely sensitive and presents numerous longitudinal ridges on its surface. According to some anatomists, the nail bed is the portion covered by the body of the nail, the nail bed being only the part on which the root of the nail rests. SYN: m. unguis [TA] , keratogenous membrane, nail bed, onychostroma. nuclear m. the network of protein fibers both around the outside of the nucleus as well as inside the nucleus. square m. a m. in which the numbers of rows and columns are equal. territorial m. SYN: cartilage capsule. m. unguis [TA] SYN: nail m..

SYN: substance. SEE ALSO: substance. [L. materies, substance] gray m. [TA] those regions of the brain and spinal cord which are made up primarily of the cell bodies and dendrites of nerve cells rather than myelinated axons. SYN: gray substance [TA] , substantia grisea [TA] , substantia cinerea. pontine gray m. SYN: pontine nuclei, under nucleus. white m. [TA] those regions of the brain and spinal cord that are largely or entirely composed of nerve fibers and contain few or no neuronal cell bodies or dendrites. SYN: alba, substantia alba, white substance.

maturate (mat′u-rat)
To suppurate. [L. maturo, pp. -atus, to make ripe, fr. maturus, ripe]

maturation (mat-u-ra′shun)
1. Achievement of full development or growth. 2. Developmental changes that lead to maturity. 3. Processing of a macromolecule; e.g., posttranscriptional modification of RNA or posttranslational modification of proteins. 4. The overall process leading to the incorporation of a viral genome into a capsid and the development of a complete virion. [L. maturatio, a ripening, fr. maturus, ripe]

mature (ma-choor′, -toor)
1. Ripe; fully developed. 2. To ripen; to become fully developed. [L. maturus, ripe]

maturity (ma-choor′i-te)
A state of full development or completed growth.

Mauchart, Mauchard
Burkhard D., German anatomist, 1696–1751. See M. ligaments, under ligament.

Georg, German physician in Sumatra, *1909. See M. clefts, under cleft, M. dots, under dot.

Pierre, French physician, *1882. See M. syndrome.

François, French obstetrician, 1637–1709. See M. maneuver, M.-Levret maneuver.

Ludwig, Austrian ophthalmologist, 1840–1894. See M. sheath.

maxilla, gen. and pl. maxillae (mak-sil′a, mak-sil′e) [TA]
An irregularly shaped pneumatized bone, supporting the superior teeth and taking part in the formation of the orbit, hard palate, and nasal cavity and containing the maxillary sinus. SYN: upper jaw bone, upper jaw. [L. jawbone]

maxillary (mak′si-lar-e)
Relating to the maxilla, or upper jaw.


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