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Medical Dictionary


schwannosis (shwah-no′sis)
A nonneoplastic proliferation of Schwann cells in the perivascular spaces of the spinal cord; seen particularly in older patients, especially those with diabetes mellitus.

Henry G., U.S. neurosurgeon, *1909. See S. tractotomy.

Oscar, U.S. pediatrician, *1919. See S. syndrome.

Franz, German physiologist, 1834–1871. See sheath of Schweigger-Seidel.

Ernst, German dermatologist, 1850–1924. See S.-Buzzi anetoderma, S. method.

sciage (se-ahzh′)
A to-and-fro, sawlike movement of the hand in massage. [Fr. scie, saw]

sciatic (si-at′ik)
1. Relating to or situated in the neighborhood of the ischium or hip. Ischial or s.. SYN: ischiadic, ischial, ischiatic. 2. Relating to sciatica. SYN: ischiadicus. [Mediev. L. sciaticus, a corruption of G. ischiadikos, fr. ischion, the hip joint]

sciatica (si-at′i-ka)
Pain in the lower back and hip radiating down the back of the thigh into the leg, initially attributed to sciatic nerve dysfunction (hence the term), but now known to usually be due to herniated lumbar disk compromising a nerve root, most commonly the L5 or S1 root. SYN: sciatic neuralgia, sciatic neuritis. [see sciatic]

Abbreviation for severe combined immunodeficiency.

SCID mice
Abbreviation for severe combined immunodeficient mice.

science (si′ens)
1. The branch of knowledge that produces theoretical explanations of natural phenomena based on experiments and observations. 2. An area of such knowledge that is restricted to explaining a limited class of phenomena. [L. scientia, knowledge, fr. scio, to know]

scientometrics (si-en-to-met′riks)
The measurement of scientific output, and the impact of scientific findings, e.g., on public policy. [L. scientia, science, knowledge, fr. scio, to know, + G. metron, measure, + -ics]

scilla (sil′a)
SYN: squill. [G.]

scillaren (sil′la-ren)
A mixture of glycosides, possessing digitalis-like actions, present in squill. s. A a crystalline steroidal glycoside (Scilla maritima), present in squill that can be hydrolyzed to glucose and proscillaridin A; the latter can be hydrolyzed to rhamnose and the steroid aglycone scillaridin A; has the same actions and uses as digitalis glycosides. SYN: transvaalin. s. B an amorphous glycosidal fraction obtained from squill, consisting of at least seven cardioactive glycosides: glucoscillaren A, scillipheoside, glucoscillipheoside, scillicryptoside, scilliglaucoside, scillicyanoside, and scillazuroside.

scillaricide (sil′ar-i-sid)
A toxic principle from squill used as a rodenticide.

scilliroside (sil′ir-o-sid)
Glycoside from red squill, the red variety of Urginea maritima (family Liliaceae). Used as a rodenticide.

scinticisternography (sin′ti-sis-tern-og′ra-fe)
Cisternography performed with a radiopharmaceutical and recorded with a radionuclide imaging device.

scintigram (sin′ti-gram)
SYN: scintiscan. [L. scintilla, spark, + G. gramma, something written]

scintigraphic (sin′ti-graf′ik)
Relating to or obtained by scintigraphy.

scintigraphy (sin-tig′ra-fe)
A diagnostic procedure consisting of the administration of a radionuclide with an affinity for the organ or tissue of interest, followed by recording the distribution of the radioactivity with a stationary or scanning external scintillation camera. See gamma camera.

scintillascope (sin-til′a-skop)
Obsolete term for scintillation counter. [L. scintilla, spark, + G. skopeo, to observe]

scintillation (sin-ti-la′shun)
1. Flashing or sparkling; a subjective sensation as of sparks or flashes of light. 2. In radiation measurement, the light produced by an ionizing event in a phosphor, as in a crystal or liquid scintillator. SEE ALSO: s. counter. [L. scintilla, a spark]

scintillator (sin′ti-la-ter, -tor)
A substance that emits visible light when hit by a subatomic particle or x- or gamma ray. SEE ALSO: scintillation counter. liquid s. a liquid with the properties of a s., in which the substance whose radioactivity is to be measured can be dissolved, to be placed in a well counter.

scintillometer (sin-ti-lom′e-ter)
SYN: scintillation counter. [L. scintilla, spark, + G. metron, measure]

scintimammography (sin′te-mam-og′ra-fe)
Breast imaging that uses a radionuclide for the detection of cancer.

scintiphotograph (sin-ti-fo′to-graf)
The image obtained by scintiphotography; obsolete. SEE ALSO: scintiscan.

scintiphotography (sin′ti-fo-tog′ra-fe)
The process of obtaining a photographic recording of the distribution of an internally administered radiopharmaceutical with the use of a gamma camera; obsolete. SYN: scintography.

scintiscan (sin′ti-skan)
The record obtained by scintigraphy. SEE ALSO: scan. SYN: photoscan, scintigram.

scintiscanner (sin′ti-skan′er)
The apparatus used to make a scintiscan.

scintography (sin-tog′ra-te)
SYN: scintiphotography.

scion (si′on)
In experimental embryology, an embryonic tissue or part grafted to another embryo of the same or of another species. SEE ALSO: chimera. [O. Fr. sion, shoot, sprig, fr. L. seco, to cut]

scirrhosity (skir-os′i-te, sir-)
A scirrhous state or hardness of a tumor.

scirrhous (skir′us, sir′)
Hard; relating to a scirrhus.

scirrhus (skir′us, sir′)
Obsolete term for any fibrous indurated area, especially an indurated carcinoma. [G. skirrhos, hard, a hard tumor]

scission (sizh′un)
1. A separation, division, or splitting, as in fission. 2. SYN: cleavage (2) . [L. scissio, fr. scindo, pp. scissus, to cleave]

scissiparity (sis-i-par′i-te)
SYN: schizogenesis. [L. scissio, cleavage, + pario, to bring forth]

scissors (siz′erz)
An instrument with two blades, moving on a pivot, that cut against each other. SYN: shears. [L. scindo, pp. scissus, to cut] de Wecker s. a small s. with sharp points for intraocular cutting of the iris and lens capsule. Smellie s. obsolete term for lance-pointed shears, with external cutting edges, used for fetal craniotomy.

A distorted image seen in mixed astigmatism by retinoscopy.

scissura, pl .scissurae (si-soo′ra, -re)
1. Cleft or fissure. 2. A splitting. SYN: scissure. [L.] s. pilorum SYN: schizotrichia.

scissure (sish′oor)
SYN: scissura.

See sclero-.

sclera, pl .sclerassclerae (skler′a, -az, -e) [TA]
A portion of the fibrous layer forming the outer envelope of the eyeball, except for its anterior sixth, which is the cornea. SYN: sclerotic coat, sclerotica, tunica albuginea oculi, tunica sclerotica. [Mod. L. fr. G. skleros, hard] blue s. appearance of the uveal tissue through a thin s. seen in a number of conditions including myopia, buphthalmos, scleral staphyloma, Ehlers-Danlos syndrome, Marfan syndrome, osteogenesis imperfecta, Paget disease, and Pierre Robin syndrome.

scleradenitis (skler′ad-e-ni′tis)
Inflammatory induration of a gland. [scler- + G. aden, gland, + -itis, inflammation]

scleral (skler′al)
Relating to the sclera. SYN: sclerotic (2) .

scleratogenous (skler-a-toj′e-nus)
SYN: sclerogenous.

sclerectasia (skler-ek-ta′ze-a)
Localized bulging of the sclera. SYN: scleral ectasia. [scler- + G. ektasis, an extension] partial s. partial protrusion of a portion of the sclera, typically seen in severe myopia. See staphyloma. total s. uniform stretching of the entire sclera, typically seen in buphthalmos.

sclerectomy (skle-rek′to-me)
1. Excision of a portion of the sclera. 2. Removal of the fibrous adhesions formed in chronic otitis media. [scler- + G. ektome, excision]

scleredema (skler-e-de′ma)
Hard nonpitting edema of the skin of the dorsal aspect of the upper body and extremities, giving a waxy appearance and no sharp demarcation; seen in diabetics and in s. adultorum. [scler- + G. oidema, a swelling (edema)] s. adultorum a benign spreading induration of the skin and subcutaneous tissue, possibly streptoccocal in origin, that may follow a febrile illness, with nonpitting thickening and induration of the skin by collagen and mucin deposit appearing first on the head and neck and extending over the trunk; a misnomer, because the disease is not restricted to adults. SYN: Buschke disease.

sclerema (skle-re′ma)
Induration of subcutaneous fat. [scler- + edema] s. neonatorum s. appearing at birth or in early infancy, usually in premature and hypothermic infants, as sharply demarcated and yellowish white indurated plaques that usually involve the cheeks, buttocks, shoulders, and calves; subcutaneous fat has a high proportion of saturated fatty acids; microscopically, there is thickening of interlobular fibrous tissue and formation of triglyceride crystals and foreign body giant cells; prognosis is poor for widespread lesions, but localized lesions may resolve slowly over a period of many months.

sclerencephaly, sclerencephalia (skler-en-sef′a-le, -en-se-fa′le-a)
Sclerosis and shrinkage of the brain substance. [scler- + G. enkephalos, brain]

scleritis (skle-ri′tis)
Inflammation of the sclera. anterior s. inflammation of the sclera adjacent to the cornea. anular s. an often protracted inflammation of the anterior portion of the sclera, forming a ring around the corneoscleral limbus. brawny s. a gelatinous-appearing swelling surrounding, and with a tendency to involve the periphery of, the cornea. SYN: gelatinous s.. deep s. severe inflammation of the sclera, with involvement of the underlying uvea. gelatinous s. SYN: brawny s.. malignant s. progressive inflammation of the anterior sclera and adjacent choroid with associated uveitis. necrotizing s. fibrinoid degeneration and necrosis of the sclera. nodular s. firm, immobile, single or multiple areas of localized s.. posterior s. inflammation, often monocular, of the sclera adjacent to the optic nerve, with frequent extension to the retina and choroid.

sclero-, scler-
Hardness (induration), sclerosis, relationship to sclera. [G. skleros, hard]

scleroatrophy (skler-o-at′ro-fe)
SYN: sclerotylosis.

scleroblastema (skler-o-blas-te′ma)
The embryonic tissue entering into the formation of bone. [sclero- + G. blastema, sprout]

sclerochoroidal (skler-o-ko-roy′dal)
Relating to both the sclera and the choroid.

sclerochoroiditis (skler′o-ko-roy-di′tis)
Inflammation of the sclera and choroid. s. anterior a secondary inflammation of the sclera by an extension of a process from the uvea. s. posterior SYN: posterior staphyloma.

scleroconjunctival (skler′o-kon-jungk-ti′val)
Relating to the sclera and the conjunctiva.

sclerocornea (skler-o-kor′ne-a)
1. The cornea and sclera regarded as forming together the hard outer coat of the eye, the fibrous tunic of the eye. 2. A congenital anomaly in which the whole or part of the cornea is opaque and resembles the sclera; other ocular abnormalities are frequently present.

sclerodactyly, sclerodactylia (skler-o-dak′ti-le, -dak-til′e-a)
SYN: acrosclerosis. [sclero- + G. daktylos, finger or toe]

scleroderma (skler-o-der′ma)
Thickening and induration of the skin caused by new collagen formation, with atrophy of pilosebaceous follicles; either a manifestation of progressive systemic sclerosis or localized (morphea). See systemic sclerosis, morphea. SYN: systemic s., systemic sclerosis (2) . [sclero- + G. derma, skin] linear s. localized s. with band-like lesions of skin with induration, atrophy, hyper- or hypopigmentation, which may be disfiguring with extension into underlying tissues and joint contractures. Involvement of the forehead and scalp has been called coup de sabre (q.v.). SYN: morphea linearis. localized s. SYN: morphea. progressive familial s. [MIM*181750] a syndrome characterized by calcinosis cutis, Raynaud phenomenon, sclerodactyly, and telangiectasia; usually due to s.; autosomal dominant form of progressive systemic sclerosis. systemic s. SYN: s..

sclerodermatous (skler-o-der′ma-tus)
Marked by, or resembling, scleroderma.

sclerogenous, sclerogenic (skle-roj′e-nus, skler-o-jen′ik)
Producing hard or sclerotic tissue; causing sclerosis. SYN: scleratogenous. [sclero- + G. -gen, producing]

scleroid (skler′oyd)
Indurated or sclerotic, of unusually firm texture, leathery, or of scarlike texture. SYN: sclerosal, sclerous. [sclero- + G. eidos, resemblance]


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