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Medical Dictionary


myoclonus (mi-ok′lo-nus, mi-o-klo′nus)
One or a series of shock-like contractions of a group of muscles, of variable regularity, synchrony, and symmetry, generally due to a central nervous system lesion. [myo- + G. klonos, tumult] benign m. of infancy SYN: benign infantile m.. benign infantile m. a seizure disorder of infancy in which myoclonic movements occur in the neck, trunk, and extremities; the EEG is normal, and seizures do not persist beyond 2 years of age. SYN: benign m. of infancy. m. multiplex an ill-defined disorder marked by rapid and widespread muscle contractions. SYN: paramyoclonus multiplex, polyclonia, polymyoclonus. nocturnal m. frequently repeated muscular jerks occurring at the moment of dropping off to sleep. palatal m. rhythmic contractions of the soft palate, the facial muscles, and the diaphragm, related to lesions of the olivocerebellar pathways. SEE ALSO: palatal nystagmus. stimulus sensitive m. m. induced by a variety of stimuli, e.g., talking, calculation, loud noises, tapping, etc.

myocolpitis (mi-o-kol-pi′tis)
Inflammation of the muscular tissue of the vagina. [myo- + G. kolpos, bosom (vagina), + -itis, inflammation]

myocomma, pl .myocommata (mi-o-kom′a, -kom′a-ta)
The connective tissue septum separating adjacent myotomes. SYN: myoseptum. [myo- + G. komma, a coin or the stamp of a coin]

myocrismus (mi-o-kris′mus)
A creaking sound sometimes heard on auscultation of a contracting muscle. [myo- + G. krizo, to squeak]

myocutaneous (mi-o-ku-ta′ne-us)
SYN: musculocutaneous. [myo- + L. cutis, skin]

myocyte (mi′o-sit)
A muscle cell. [myo- + G. kytos, cell] Anitschkow m. SYN: cardiac histiocyte.

myocytolysis (mi-o-si-tol′i-sis)
Dissolution of muscle fiber. [myo- + G. kytos, cell, + lysis, a loosening] m. of heart local loss of myocardial syncytium as a result of a metabolic imbalance, insufficient in intensity or duration (or both) to cause stromal injury or to elicit any reactive exudation.

myocytoma (mi′o-si-to′ma)
A benign neoplasm derived from muscle.

myodegeneration (mi′o-de-jen-e-ra′shun)
Muscular degeneration.

myodemia (mi-o-de′me-a)
Fatty degeneration of muscle. [myo- + G. demos, tallow]

myodermal (mi-o-der′mal)
SYN: musculocutaneous. [myo- + G. derma, skin]

myodiastasis (mi′o-di-as′ta-sis)
Separation of muscle. [myo- + G. diastasis, separation]

myodynamia (mi′o-di-na′me-a)
Muscular strength. [myo- + G. dynamis, power]

myodynamics (mi′o-di-nam′iks)
The dynamics of muscular action.

myodynamometer (mi′o-di-na-mom′e-ter)
An instrument for determining muscular strength. [myo- + G. dynamis, force, + metron, measure]

myodynia (mi′o-din′e-a)
SYN: myalgia. [myo- + G. odyne, pain]

myodystony (mi-o-dis′to-ne)
A condition of slow relaxation, interrupted by a succession of slight contractions, following electrical stimulation of a muscle. [myo- + G. dys-, difficult, + tonos, tone, tension]

myodystrophy, myodystrophia (mi-o-dis′tro-fe, mi′-o-dis-tro′fe-a)
SYN: muscular dystrophy. [myo- + G. dys-, difficult, poor, + trophe, nourishment]

myoedema (mi′o-e-de′ma)
A localized contraction of a degenerating muscle, occurring at the point of a sharp blow, independent of the nerve supply. SYN: idiomuscular contraction, mounding, myoidema. [myo- + G. oidema, swelling]

myoelastic (mi′o-e-las′tik)
Pertaining to closely associated smooth muscle fibers and elastic connective tissue.

myoelectric (mi′o-e-lek′trik)
Relating to the electrical properties of muscle.

myoendocarditis (mi-o-en′do-kar-di′tis)
Inflammation of the muscular wall and lining membrane of the heart. [myo- + G. endon, within, + kardia, heart, + -itis, inflammation]

myoepithelial (mi′o-ep-i-the′le-al)
Relating to myoepithelium.

myoepithelioma (mi′o-ep-i-the-le-o′ma)
A benign tumor of myoepithelial cells. [myo- + epithelium, + G. -oma, tumor]

myoepithelium (mi′o-ep-i-the′le-um)
Spindle-shaped, contractile, smooth musclelike cells of epithelial origin that are arranged longitudinally or obliquely around sweat glands and the secretory alveoli of the mammary gland; stellate myoepithelial cells occur around lacrimal and some salivary gland secretory units. SYN: muscle epithelium. [myo- + epithelium]

myoesthesis, myoesthesia (mi′o-es-the′sis, -the′ze-a)
SYN: kinesthetic sense.

myofascial (mi-o-fash′e-al)
Of or relating to the fascia surrounding and separating muscle tissue.

myofascitis (mi′o-fa-si′tis)
SYN: myositis fibrosa.

myofibril (mi-o-fi′bril)
One of the fine longitudinal fibrils occurring in a skeletal or cardiac muscle fiber comprising many regularly overlapped ultramicroscopic thick and thin myofilaments. SYN: muscular fibril, myofibrilla. [myo- + Mod. L. fibrilla, fibril]

myofibrilla, pl .myofibrillae (mi′o-fi-bril′a, -bril′e)
SYN: myofibril.

myofibrillar (mi-o-fi-bril-ar)
Pertaining or relating to myofibril.

myofibroblast (mi-o-fi′bro-blast)
A cell thought to be responsible for contracture of wounds; such cells have some characteristics of smooth muscle, such as contractile properties and fibrils, and are also believed to produce, temporarily, type III collagen.

myofibroma (mi′o-fi-bro′ma)
A benign neoplasm that consists chiefly of fibrous connective tissue, with variable numbers of muscle cells forming portions of the neoplasm.

myofibromatosis (mi-′yo-fi-bro-ma- to′sis)
Solitary or multiple tumors of muscle and fibrous tissue, or tumors composed by myofibroblasts. [myo- + L. fibra, fiber, + G. suffix, -oma, tumor, + suffix -osis, condition] infantile m. m. seen at birth or in infants, with multiple lytic bone lesions and involving soft tissue, or with visceral involvement.

myofibrosis (mi′o-fi-bro′sis)
Chronic myositis with diffuse hyperplasia of the interstitial connective tissue pressing upon and causing atrophy of the muscular tissue. m. cordis m. of the heart walls.

myofibrositis (mi′o-fi-bro-si′tis)
Inflammation of the perimysium.

myofilaments (mi-o-fil′a-ments)
The ultramicroscopic threads of filamentous proteins making up myofibrils in striated muscle. Thick ones contain myosin and thin ones actin; thick and thin m. also occur in smooth muscle fibers but are not regularly arranged in discrete myofibrils and thus do not impart a striated appearance to these cells.

myofunctional (mi′o-funk′shun-al)
1. Relating to function of muscles. 2. In dentistry, relating to the role of muscle function in the etiology or correction of orthodontic problems.

myogen (mi′o-jen)
Proteins extracted from skeletal muscle with cold water, largely the enzymes promoting glycolysis; from the residue, alkaline 0.6 mol L−1 KCl extracts actin and myosin as actomyosin, with myosin further separable into two meromyosins by proteinase treatment. SYN: myosinogen. [myo- + G. -gen, producing]

myogenesis (mi-o-jen′e-sis)
Embryonic formation of muscle cells or fibers. [myo- + G. genesis, origin]

myogenetic, myogenic (mi-o-je-net′ik, -jen′ik)
1. Originating in or starting from muscle. 2. Relating to the origin of muscle cells or fibers. SYN: myogenous.

myogenous (mi-oj′e-nus)
SYN: myogenetic.

myoglobin (Mb, MbCO, MbO2) (mi-o-glo′bin)
The oxygen-carrying and storage protein of muscle, resembling blood hemoglobin in function but containing only one subunit and one heme as part of the molecule (rather than the four of hemoglobin), and with a molecular weight approximately one-quarter that of hemoglobin. SYN: muscle hemoglobin, myohemoglobin. [myo- + hemoglobin] carbonmonoxy m. SYN: carboxyhemoglobin.

myoglobinuria (mi′o-glo-bi-noo′re-a)
Excretion of myoglobin in the urine; results from muscle degeneration, which releases myoglobin into the blood; occurs in certain types of trauma (crush syndrome), advanced or protracted ischemia of muscle, or as a paroxysmal process of unknown etiology. SYN: idiopathic paroxysmal rhabdomyolysis, Meyer-Betz disease, Meyer-Betz syndrome.

myoglobulin (mi-o-glob′u-lin)
Globulin present in muscle tissue.

myoglobulinuria (mi′o-glob′u-li-noo′re-a)
The excretion of myoglobulin in the urine.

myognathus (mi-og′na-thus, mi-o-nath′us)
An unequal conjoined twin in which the rudimentary head of the parasite is attached to the lower jaw of the autosite by muscle and skin only. See conjoined twins, under twin. [myo- + G. gnathos, jaw]

myogram (mi′o-gram)
The tracing made by a myograph. SYN: muscle curve. [myo- + G. gramma, a drawing]

myograph (mi′o-graf)
A recording instrument by which tracings are made of muscular contractions. [myo- + G. grapho, to write] palate m. SYN: palatograph.

myographic (mi-o-graf′ik)
Relating to a myogram, or the record of a myograph.

myography (mi-og′ra-fe)
1. The recording of muscular movements by the myograph. 2. A description of or treatise on the muscles. SYN: descriptive myology.

myohemoglobin (mi′o-hem-o-glo′bin)
SYN: myoglobin.

myoid (mi′oyd)
1. Resembling muscle. 2. One of the fine, contractile, threadlike protoplasmic elements found in certain epithelial cells in lower animals. 3. A contractile part of retinal cones in certain fish and amphibia. In mammals, the m. is the inner part of the inner segment of rods and cones; it contains microtubules, the Golgi apparatus, endoplasmic reticulum, and ribosomes, but no myofibrils. [myo- + G. eidos, appearance]

myoidema (mi-oy-de′ma)
SYN: myoedema. [myo- + G. oidema, swelling]

myoinositol (mi-o-in-o′-si-tol)
See myo-inositol.

myoischemia (mi′o-is-ke′me-a)
A condition of localized deficiency or absence of blood supply in muscular tissue.

myokerosis (mi′o-ke-ro′sis)
SYN: myocerosis.

myokinase (mi-o-ki′nas)
SYN: adenylate kinase.

myokinesimeter (mi′o-kin-e-sim′e-ter)
A device for registering the exact time and extent of contraction of the larger muscles of the lower extremity in response to electric stimulation. SYN: myocinesimeter. [myo- + G. kinesis, movement, + metron, measure]

myokymia (mi-o-ki′me-a)
Continuous involuntary quivering or rippling of muscles at rest, caused by spontaneous, repetitive firing of groups of motor unit potentials. SYN: fibrillary chorea, Morvan chorea. [myo- + G. kyma, wave] facial m. m. that appears in the facial muscles, causing narrowing of the palpebral fissure and continuous undulation of the facial skin surface; the latter is referred to as “bag of worms” appearance and is best seen with reflected light; due to intrinsic brainstem lesion, such as a pontine glioma or multiple sclerosis. generalized m. widespread m., present in multiple limbs and often the face; of various causes, including Isaac syndrome, uremia, thyrotoxicosis and gold toxicity (gold-m. syndrome). hereditary m. [MIM*160100] a syndrome consisting of muscle contractions and night cramps; autosomal dominant inheritance. limb m. m. present in one or more limbs; various causes, one of the more common being prior plexus radiation.

myolemma (mi-o-lem′a)
SYN: sarcolemma.

myolipoma (mi′o-li-po′ma)
A benign neoplasm that consists chiefly of fat cells (adipose tissue), with variable numbers of muscle cells forming portions of the neoplasm.

myologia (mi′o-lo′je-a)
SYN: myology.

myologist (mi-ol′o-jist)
One learned in the knowledge of muscles.

myology (mi-ol′o-je)
The branch of science concerned with the muscles and their accessory parts, tendons, aponeuroses, bursae, and fasciae. SYN: myologia, sarcology (1) . [myo- + G. logos, study] descriptive m. SYN: myography (2) .

myolysis (mi-ol′i-sis)
Dissolution or liquefaction of muscular tissue, frequently preceded by degenerative changes such as infiltration of fat, atrophy, and fatty degeneration. [myo- + G. lysis, dissolution] cardiotoxic m. cardiomalacia occurring in fever and various systemic infections.

myoma (mi-o′ma)
A benign neoplasm of muscular tissue. SEE ALSO: leiomyoma, rhabdomyoma. [myo- + G. -oma, tumor]

myomalacia (mi′o-ma-la′she-a)
Pathologic softening of muscular tissue. [myo- + G. malakia, softness]

myomatous (mi-o′ma-tus)
Pertaining to or characterized by the features of a myoma.

myomectomy (mi-o-mek′to-me)
Operative removal of a myoma, specifically of a uterine myoma. SYN: fibroidectomy, fibromectomy, hysteromyomectomy. [myoma + G. ektome, excision] abdominal m. removal of a myoma of the uterus through an abdominal incision. left ventricular m. resection of myocardial tissue used in cases of idiopathic hypertrophic subaortic stenosis. vaginal m. removal of a myoma of the uterus through the vagina. SYN: colpomyomectomy.


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