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Medical Dictionary


1. Any spot, line, or other figure on the cutaneous or mucocutaneous surface, visible through difference in color, elevation, or other peculiarity. [A.S. mearc] alignment m. marks made in tracings while the kymograph or other recording apparatus is at rest in order to indicate the time relations between two tracings inscribed one above the other, e.g., jugular and radial pulses. stretch marks SYN: striae cutis distensae, under stria.

1. A device used to make a mark or to indicate measurement. 2. A characteristic or factor by which a cell or molecule can be recognized or identified. 3. A locus containing two or more alleles that, being harmless, are common and therefore yield high frequencies of heterozygotes which facilitate linkage analysis. allotypic m. SYN: allotype. cell m. an identifying characteristic of a cell; e.g., formation of rosettes with sheep erythrocytes as a m. of T lymphocytes, or the presence of surface immunoglobulin as a m. of B lymphocytes. cell surface m. a surface protein, glycoprotein, or group of proteins that distinguish a cell or subset of cells from another defined subset of cells. genetic m. SYN: genetic determinant. linkage m. a locus at which there is a high probability of heterozygotes (indispensible state for linkage analysis), but in itself perhaps of no clinical interest. SEE ALSO: m. locus. oncofetal m. a tumor m. produced by tumor tissue and by fetal tissue of the same type as the tumor, but not by normal adult tissue from which the tumor arises. polymorphic genetic m. inherited characteristic that occurs within a given population as two or more traits. time m. an instrument that marks the time, usually in seconds or fractions of seconds, on a kymograph record in physiologic experiments. tumor m. a substance, released into the circulation by tumor tissue, whose detection in the serum indicates the presence of tumor.

Andrei, Russian mathematician, 1865–1922. See M. process.

Marme reagent
See under reagent.

marmorated (mar′mo-ra-ted)
Denoting a condition in which the appearance of the skin is streaked like marble. SEE ALSO: cutis marmorata. [L. marmoratus, marbled]

marmot (mar′mot)
A woodchuck or groundhog; a hibernating rodent that may serve as reservoir host of plague bacillus in North America. [Fr. marmotte]

Pierre, French medical geneticist, *1926. See M.-Lamy syndrome.

Marquis reagent
See under reagent.

marrow (mar′o) [TA]
1. A highly cellular hematopoietic connective tissue filling the medullary cavities and spongy epiphyses of bones; it becomes predominantly fatty with age, particularly in the long bones of the limbs. 2. Any soft gelatinous or fatty material resembling the m. of bone. SEE ALSO: medulla. [A.S. mearh] bone m. [TA] the soft, pulpy tissue filling the medullary cavities of bones, having a stroma of reticular fibers and cells; it differs in consistency by age and location. SEE ALSO: gelatinous bone m., red bone m., yellow bone m.. SYN: medulla ossium [TA] . gelatinous bone m. [TA] degenerated m. of cranial bones in old age. red bone m. [TA] bone m. in which the stroma primarily contain the developmental stages of erythrocytes, leukocytes, and megakaryocytes; it is present throughout the skeleton during fetal life and at birth. After the fifth postnatal year, it is gradually replaced in the long bones by yellow m.. SYN: medulla ossium rubra [TA] . spinal m. SYN: spinal cord. yellow bone m. [TA] bone m. in which the stroma of the reticular network are largely filled primarily with fat; it replaces red m. in the long bones after the fifth year of life. SYN: medulla ossium flava [TA] .

Don, U.S. ophthalmologist, *1905. See M. syndrome.

Eli K., U.S. pharmacologist, 1889–1966. See M. method.

John, English anatomist, 1818–1891. See M. vestigial fold, M. oblique vein.

Victor F., U.S. urologist, *1913. See M. test, M.-Marchetti test, M.-Marchetti-Krantz operation.

Marshallagia marshalli (mar-sha-la′je-a mar-shal′i)
One of the medium stomach worms of the nematode family Trichostrongylidae, found in the abomasum of sheep, goats, camels, and various wild ruminants.

marshmallow root (marsh′mal-o)
SYN: althea.

marsupial (mar-soo′pe-al)
1. A member of the order Marsupalia, which includes such mammals as kangaroos, wombats, bandicoots, and opossums, the female of which has an abdominal pouch for carrying the young. 2. Of or pertaining to marsupials. [L. marsupium, a pouch]

marsupialization (mar-soo′pe-al-i-za′shun)
Exteriorization of a cyst or other such enclosed cavity by resecting the anterior wall and suturing the cut edges of the remaining wall to adjacent edges of the skin, thereby creating a pouch. [L. marsupium, pouch]

marsupium (mar-soo′pe-um)
1. SYN: scrotum. 2. A pouch or sac; e.g., in marsupials. [L. pouch]

J., 19th century Italian anatomist. See M. area, M. funnel.

August E., German gynecologist, 1847–1933. See M. tube, M.-Gruber anastomosis.

Henry A., U.S. surgeon, 1824–1884. See M. bandage, M. disease.

J.E. See Thayer-M. medium.

Giovanni, Italian physician, 1857–1928. See M. cell.

martius yellow (marsh′e-us) [C.I. 10315]
An acid dye used as a stain in plant and animal histology, and as a light filter for photomicrography. [Karl A. Martius, Ger. chemist, *1920]

Fernando Otzet, Spanish cardiologist, 1906–1984. See M. syndrome.

Maryland coma scale
See coma scale.

maschale (mas′kal-e)
SYN: axilla. [G.]

maschalyperidrosis (mas′kal-i-per-i-dro′sis)
Excessive sweating in the axillae. [G. maschale, axilla, + hyper, over, + hidros, sweat]

masculine (mas′ku-lin)
Relating to or marked by the characteristics of the male sex or gender. SYN: male (2) , masculinus. [L. masculus, male, fr. mas, male]

masculine protest
Adler term to describe the movement of individuals from passive to active roles in a desire to escape from the feminine role.

masculinity (mas-ku-lin′i-te)
The qualities and characteristics of a male.

masculinization (mas′ku-lin-i-za′shun)
The condition marked by the attainment of male characteristics, such as facial hair, either physiologically as part of male maturation, or pathologically by individuals of either sex. [L. masculus, male]

masculinize (mas′ku-li-niz)
To confer the qualities or characteristics peculiar to the male.

masculinus (mas-ku-li′nus)
SYN: masculine, masculine. [L.]

Giulio, Italian physician, 1874–1937.

mask (mask)
1. Any of a variety of disease states producing alteration or discoloration of the skin of the face. 2. The expressionless appearance seen in certain diseases; e.g., Parkinson facies. 3. A facial bandage. 4. A shield designed to cover the mouth and nose for maintenance of antiseptic conditions. 5. A device designed to cover the mouth and nose for administration of inhalation anesthetics, oxygen, or other gases. ecchymotic m. a dusky discoloration of the head and neck occurring when the trunk has been subjected to sudden and extreme compression, as in traumatic asphyxia. Hutchinson m. the sensation experienced in tabetic neurosyphilis as if the face were covered with a m. or with cobwebs. laryngeal m. a tubular oropharyngeal airway with an inflatable rim at the distal end that when inflated creates an airtight seal immediately above the larynx. nonrebreathing m. a m. fitted with both an inhalation valve and an exhalation valve so that all exhaled gas is vented to the external atmosphere and inhaled gas comes only from a reservoir connected to the m.. tropical m. SYN: chloasma bronzinum.

masked (maskt)

1. The use of noise of any kind to interfere with the audibility of another sound. For any given intensity, low-pitched tones have a greater m. effect than those of a high pitch. 2. In audiology, the use of a noise applied to one ear while testing the hearing of the other ear. 3. The hiding of smaller rhythms in the brain wave record by larger and slower ones whose wave form they distort. 4. In dentistry, an opaque covering used to camouflage the metal parts of a prosthesis. 5. In radiography, superimposition of an altered positive image on the original negative to produce an enhanced copy photographically. See subtraction. unsharp m. in radiography, superimposing a blurred negative of a radiograph to cancel large density differences, leaving fine detail more visible.

Abraham H., U. S. psychologist, 1908–1970. See M. hierarchy.

masochism (mas′o-kizm, maz′o-)
1. Passive algolagnia; a form of perversion, often sexual in nature, in which a person experiences pleasure in being abused, humiliated, or maltreated. Cf.:sadism. 2. A general orientation in life that personal suffering relieves guilt and leads to a reward. [Leopold von Sacher-Masoch, Austrian novelist, 1836–1895]

masochist (mas′o-kist)
The passive party in the practice of masochism.

Edward E., U.S. surgeon, *1920.

Acronym for mitral valve prolapse, aortic anomalies, skeletal changes, and skin changes. See M. syndrome.

mass (m)
1. A lump or aggregation of coherent material. SYN: massa [TA] . 2. In pharmacy, a soft solid preparation containing an active medicinal agent, of such consistency that it can be divided into small pieces and rolled into pills. 3. One of the seven fundamental quantities in the SI system; its unit is the kilogram, defined as the m. of the international prototype of the kilogram, which is made of platinum-iridium and kept at the International Bureau of Weights and Measures. 4. The quantity of matter in a body or substance. [L. massa, a doughlike m.] apperceptive m. the already existing knowledge base in a similar or related area with which the new perceptual material is articulated. filar m. SYN: reticular substance (1) . injection m. colored solutions or suspensions injected into the vascular system to render vessels and their walls prominent; useful for gross preparations and for study under low magnification after clearing; most fluids contain warm gelatin and the coloring materials are carmine, Berlin blue, or carbon. inner cell m. the cells at the embryonic pole of the blastocyst concerned with formation of the body of the embryo per se. SYN: embryoblast. intermediate m. SYN: interthalamic adhesion. lateral m. of atlas [TA] the thick weight-bearing lateral part of the atlas on each side that articulates above with the occipital condyle and below with the axis. SYN: massa lateralis atlantis [TA] . lateral m. of ethmoid bone SYN: ethmoidal labyrinth. molar m. molecular weight. molecular m. SYN: molecular weight. pilular m. the mixture of drug(s), excipients, diluents and binders with a suitable amount of liquid to form a plastic m. which can be rolled into a long rod and cut into the appropriate number of units for pills to be rolled from. SYN: pill m.. relative molecular m. (Mr) SYN: molecular weight. sclerotic cemental m. benign fibro-osseous jaw lesions of unknown etiology, occurring predominantly in middle-aged black females, which present as large painless radiopaque masses usually involving several quadrants of the jaw. SYN: florid osseous dysplasia, cemental dysplasia. tubular excretory m. the m. of functioning excretory tubules of the kidney determined from the excretion of measurable compounds processed in the kidney primarily by tubular secretion.

massa, gen. and pl. massae (mas′sa, mas′se) [TA]
SYN: mass (1) . [L.] m. intermedia interthalamic adhesion. m. lateralis atlantis [TA] SYN: lateral mass of atlas.

massage (ma-sahzh′)
A method of manipulation of the body or portion thereof by rubbing, pinching, kneading, tapping, etc. SYN: tripsis (2) . [Fr. from G. masso, to knead] cardiac m. SYN: heart m.. closed chest m. rhythmic compression of the heart between sternum and spine by depressing the lower sternum backward with the heels of the hands, the patient lying supine. SYN: external cardiac m.. external cardiac m. SYN: closed chest m.. gingival m. mechanical stimulation of the gingiva by rubbing or pressure. heart m. rhythmic m. of the heart either in an open chest or through the chest wall to renew failed circulation during cardiac resuscitation. SYN: cardiac m.. open chest m. rhythmic manual compression of the ventricles of the heart with the hand inside the thoracic cavity. prostatic m. 1. manual expression of prostatic secretions by digital rectal technique; 2. the emptying of prostatic acini and ducts by repeated downward compression maneuvers, for treatment of various congestive and inflammatory prostatic conditions. vibratory m. very rapid tapping of the surface effected by means of an instrument, usually with an elastic tip. SYN: seismotherapy, sismotherapy, vibrotherapeutics.

Julián, French physician, 1844–1917. See M. spectacles.

See m. (muscle).

masseur (ma-ser′)
1. A man who massages. 2. An instrument used in mechanical massage. [Fr. see massage]

masseuse (ma-sooz′)
A woman who massages.

massicot (mas′i-kot)
SYN: lead monoxide.

Pierre, Canadian pathologist, 1880–1959. See M.-Fontana ammoniac silver stain. See entries under stain.

massotherapy (mas-o-thar′a-pe)
The therapeutic use of massage. [G. masso, to knead, + therapeia, treatment]

Abbreviation for military antishock trousers.

See masto-.

mastadenitis (mast′ad-e-ni′tis)
SYN: mastitis. [masto- + G. aden, gland, + -itis, inflammation]

mastadenoma (mast′ad-e-no′ma)
An adenoma of the breast. [masto- + G. aden, gland, + -oma, tumor]

Mastadenovirus (mast-ad′e-no-vi′rus)
A genus of the family Adenoviridae, including adenoviruses that infect mammals, with over 40 antigenic types (species) being infective for humans. They cause respiratory infections in children, epidemic acute respiratory disease in military recruits, acute follicular conjunctivitis in adults, epidemic keratoconjunctivitis and gastroenteritis; many infections are inapparent. [G. mastos, breast, hence mammal, + adenovirus]

mastalgia (mas-tal′je-a)
SYN: mastodynia. [masto- + G. algos, pain]

mastatrophy, mastatrophia (mas-tat′ro-fe, mast-a-tro′fe-a)
Atrophy or wasting of the breasts. [masto- + atrophy]

mastauxe (mas-tawk′se)
Hypertrophy of the breast. [masto- + G. auxe, increase]

mastectomy (mas-tek′to-me)
Excision of the breast. SYN: mammectomy. [masto- + G. ektome, excision] extended radical m. excision of the entire breast including the nipple, areola, and overlying skin, as well as the pectoral muscles and the lymphatic-bearing tissues of the axilla and chest wall and internal mammary chain of lymph nodes. modified radical m. excision of the entire breast including the nipple, areola, and overlying skin, as well as the lymphatic-bearing tissue in the axilla with preservation of the pectoral muscles. radical m. excision of the entire breast including the nipple, areola, and overlying skin, as well as the pectoral muscles, lymphatic-bearing tissue in the axilla, and various other neighboring tissues. SYN: Halsted operation (2) . simple m. excision of the breast including the nipple, areola, and some of the overlying skin. SYN: total m.. subcutaneous m. excision of the breast tissues, but sparing the skin, nipple, and areola; usually followed by implantation of a prosthesis. total m. SYN: simple m..

Arthur M., U.S. physician, 1895–1973. See M. test, M. two-step exercise test.

William H., U.S. gynecologist, *1915. See Allen-M. syndrome.

mastic (mas′tik)
A resinous exudate from Pistacia lentiscus (family Anacardiaceae), a small tree of the Mediterranean shores; used in chewing gum, as an enteric coating, and as a temporary filling material in dentistry. SYN: mastich, mastiche. [G. mastiche, the resin of the mastich tree]


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