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Medical Dictionary


sphenomalar (sfe′no-ma′lar)
SYN: sphenozygomatic.

sphenomaxillary (sfe′no-mak′si-lar-e)
Relating to the sphenoid bone and the maxilla.

sphenooccipital (sfe′no-ok-sip′i-tal)
SYN: sphenobasilar.

sphenopalatine (sfe-no-pal′a-tin)
Relating to the sphenoid and the palatine bones.

sphenoparietal (sfe′no-pa-ri′a-tal)
Relating to the sphenoid and the parietal bones.

sphenopetrosal (sfe′no-pe-tro′sal)
Relating to the sphenoid bone and the petrous portion of the temporal bone.

sphenorbital (sfe-nor′bi-tal)
Denoting the portions of the sphenoid bone contributing to the orbits.

sphenosalpingostaphylinus (sfe′no-sal-ping′go-staf-i-li′nus)
See tensor veli palati (muscle). [L.]

sphenosquamosal (sfe′no-skwa-mo′sal)
SYN: squamosphenoid.

sphenotemporal (sfe′no-tem′po-ral)
Relating to the sphenoid and the temporal bones.

sphenotic (sfe-no′tik)
Relating to the sphenoid bone and the bony case of the ear. [spheno- + G. ous, ear]

sphenoturbinal (sfe′no-ter′bi-nal)
Denoting the concha sphenoidalis.

sphenovomerine (sfe′no-vo′mer-en, -in)
Relating to the sphenoid bone and the vomer.

sphenozygomatic (sfe′no-zi-go-mat′ik)
Relating to the sphenoid and the zygomatic bones. SYN: sphenomalar.

sphere (sfer)
A ball or globular body. [G. sphaira] attraction s. SYN: astrosphere. Morgagni spheres SYN: Morgagni globules, under globule.

spherical (sph.) (sfer′i-kal)
Pertaining to, or shaped like, a sphere.

Spherical, a sphere. [G. sphaira, globe]

spherocylinder (sfer′o-sil′in-der)
SYN: spherocylindrical lens.

spherocyte (sfer′o-sit)
A small, spherical red blood cell. [sphero- + G. kytos, cell]

spherocytosis (sfer′o-si-to′sis)
Presence of sphere-shaped red blood cells in the blood. SYN: microspherocytosis. [spherocyte + G. -osis, condition] hereditary s. [MIM*182900] a congenital defect of spectrin [MIM*182860], the main component of the erythrocyte cell membrane, which becomes abnormally permeable to sodium, resulting in thickened and almost spherical erythrocytes that are fragile and susceptible to spontaneous hemolysis, with decreased survival in the circulation; results in chronic anemia with reticulocytosis, episodes of mild jaundice due to hemolysis, and acute crises with gallstones, fever, and abdominal pain; symptomatology is highly variable; autosomal dominant inheritance, caused by mutation in the ankyrin gene (ANK1) on 8p. However, as with elliptocytosis, there is an autosomal recessive form [MIM*270970], caused by mutation in the alpha-spectrin 1 gene (SPTA1) on chromosome 1q. SYN: chronic acholuric jaundice, chronic familial icterus, chronic familial jaundice, congenital hemolytic icterus, congenital hemolytic jaundice, spherocytic anemia.

spheroid, spheroidal (sfer′oyd, sfir-; sfe-royd′al)
Shaped like a sphere. [L. spheroideus]

spherometer (sfer-om′e-ter)
An instrument to determine the curvature of a sphere or a spherical lens. See Geneva lens measure. [sphero- + G. metron, measure]

spherophakia (sfer-o-fa′ke-a)
A congenital bilateral aberration in which the lenses are small, spherical, and subject to subluxation; may occur as an independent anomaly or may be associated with the Weill-Marchesani syndrome. [sphero- + G. phakos, lens]

spheroplast (sfer′o-plast)
A bacterial cell from which the rigid cell wall has been incompletely removed. The bacterium loses its characteristic shape and becomes round. [sphero- + G. plastos, formed]

spheroprism (sfer′o-prizm)
A spherical lens decentered to produce a prismatic effect, or a combined spherical lens and prism.

spherospermia (sfer′o-sper′me-a)
Spheroid spermatozoa lacking an elongated tail, in contrast to the threadlike, tailed sperm of humans and other mammals (nematospermia). [sphero- + G. sperma, seed]

spherule (sfer′ool)
1. A small spherical structure. 2. A sporangiallike structure filled with endospores at maturity, produced within tissue and in vitro by Coccidioides immitis. [LL. sphaerula, dim. of L. sphaera, sphere, ball]

sphincter (sfingk′ter) [TA]
A muscle that encircles a duct, tube, or orifice in such a way that its contraction constricts the lumen or orifice. SYN: musculus s. [TA] , s. muscle [TA] . [G. sphinkter, a band or lace] s. of ampulla s. of hepatopancreatic ampulla. anatomic s. an accumulation of muscular circular fibers or specially arranged oblique fibers the function of which is to reduce partially or totally the lumen of a tube, the orifice of an organ, or the cavity of a viscus; the closing component of a pylorus. s. angularis, angular s. thickening of the circular muscular layer forming a proposed intermediate s. at the level of the angular notch of the stomach. While the thickening of the circular muscle may indicate the commencement of the pyloric antrum, true functional sphincteric activity distinct from the other peristaltic contractions of the stomach is not observed although some of these may in fact temporarily close off the antrum from the remainder of the stomach lumen. SYN: antral s., midgastric transverse s., s. antri, s. intermedius, s. of antrum, s. of gastric antrum. s. ani, anal s. external anal s., internal anal s.. s. ani tertius the third s. of the anorectum, a physiological s. at the sigmoidorectal junction. antral s. SYN: s. angularis. s. antri SYN: s. angularis. s. of antrum SYN: s. angularis. anular s. a short thickening of circular muscular fibers, similar to a ring; a ring-shaped s. as opposed to a segmental s.. artificial s. a s. produced by surgical procedures to reduce speed of flow in the digestive system or to maintain continence of the intestine. basal s. the thickening of the circular muscular coat at the base of the ileal papilla at the terminal ileum. SYN: sphincteroid tract of ileum. bicanalicular s. a s. encircling two canals, such as the terminal portions of the common bile duct and the main pancreatic duct. s. of biliaropancreatic ampulla s. of hepatopancreatic ampulla. Boyden s. SYN: s. of (common) bile duct. canalicular s. a s. located somewhere along the course of an organ, a tube, or a duct, as opposed to ostial s.. choledochal s. SYN: s. of (common) bile duct. colic s. one of the physiological sphincters of the colon. s. of (common) bile duct [TA] smooth muscle s. of the common bile duct immediately proximal to the hepatopancreatic ampulla and organized into a superior and inferior s.; it is this s. that controls the flow of bile in the duodenum. SYN: musculus s. ductus choledochi [TA] , musculus s. ductus biliaris&star, Boyden s., choledochal s., s. muscle of common bile duct. s. constrictor cardiae SYN: inferior esophageal s.. duodenal s. one of the physiologic sphincters described in the duodenum. duodenojejunal s. the s. supposedly present at the duodenojejunal flexure. external anal s. [TA] a fusiform ring of striated muscular fibers surrounding the anus, attached posteriorly to the coccyx and anteriorly to the central tendon of the perineum; it is subdivided, often indistinctly, into a subcutaneous part, a superficial part, and a deep part for descriptive purposes. SYN: musculus s. ani externus [TA] , external s. muscle of anus. external urethral s. [TA] muscle that constricts membranous urethra to retain urine in bladder; nerve supply, pudendal. SYN: s. urethrae externus [TA] , Guthrie muscle, musculus constrictor urethrae, musculus s. urethrae externus, s. muscle of urethra, Wilson muscle (1) . external urethral s. of female [TA] composed of striated (voluntary) muscle and more properly a urogenital s., part forms a true anular s. around the urethra, part extends superiorly to the neck of the bladder, part passing anterior to the urethra that attaches to the ischial rami (compressor urethrae muscle) and a bandlike part that encircles both the urethra and the vagina (urethrovaginal s.). SYN: musculus s. urethrae externus femininae [TA] . external urethral s. of male [TA] composed of striated (voluntary) muscle, includes a tubelike portion that encircles the membranous urethra, but also has a large, troughlike portion that ascends the anterior aspect of the prostatic urethra to the neck of the bladder and a part that passes anteriorly to the membranous urethra and attaches to the ischial rami on each side (compressor urethrae muscle). SYN: musculus s. urethrae externus masculinae [TA] . extrinsic s. a s. provided by circular muscular fibers extraneous to the organ. first duodenal s. the s. supposedly located at the level of the aboral extremity of the duodenal bulb. functional s. SYN: physiologic s.. s. of gastric antrum SYN: s. angularis. Glisson s. SYN: s. of hepatopancreatic ampulla. s. of hepatic flexure of colon physiological s. at the level of the right colic flexure. hepatopancreatic s. SYN: s. of hepatopancreatic ampulla. s. of hepatopancreatic ampulla [TA] the smooth muscle s. of the hepatopancreatic ampulla within the duodenal papilla. SYN: musculus s. ampullae hepatopancreaticae [TA] , musculus s. ampullae biliaropancreaticae&star, musculus s. ampullae&star, s. of ampulla&star, s. of biliaropancreatic ampulla&star, Glisson s., hepatopancreatic s., Oddi s.. hypertensive upper esophageal s. SYN: cricopharyngeal achalasia. Hyrtl s. a band, generally incomplete, of circular muscular fibers in the rectum about 10 cm above the anus (upper rectal ampulla). ileal s. a thickening of circular musculature at the free margin of the ileal papilla. SYN: ileocecocolic s., marginal s., operculum ilei, Varolius s.. ileocecocolic s. SYN: ileal s.. iliopelvic s. SYN: midsigmoid s.. inferior esophageal s. a physiologic s. at the level of the esophagogastric junction; this is in fact an extrinsic s. formed by the surrounding musculature of the esophageal hiagus of the right crus of the diaphragm; causes a normally occurring constriction at the esophagogastric junction observable with a barium swallow. SYN: s. constrictor cardiae. s. intermedius SYN: s. angularis. internal anal s. [TA] a smooth muscle ring, formed by an increase of the circular fibers of the rectum, situated at the upper end of the anal canal, internal to the outer voluntary external anal s.. This s. is maximally contracted when the rectal ampulla is “at rest”—empty or relaxed to accommodate a distending fecal mass. It is inhibited with filling of the ampulla, increased distension, and peristalsis. SYN: musculus s. ani internus [TA] , internal s. muscle of anus. internal urethral s. [TA] the complete collar of smooth muscle cells of the neck of the urinary bladder that extends distally to surround the preprostatic portion of the male urethra. There is not comparable structure in the neck of the female bladder; the internal urethral s. may exist to prevent reflux of semen into the bladder. SYN: musculus s. urethrae internus&star, preprostatic s.&star, supracollicular s.&star, anulus urethralis, muscular s. supracollicularis, musculus s. vesicae, preprostate urethral s., proximal urethral s., s. muscle of urinary bladder, s. vesicae. intrinsic s. a thickening of the circular fibers of the muscular coat of an organ. lower esophageal s. (LES) musculature of the gastroesophageal junction that is tonically active except during swallowing. macroscopic s. a s. visible to the naked eye. marginal s. SYN: ileal s.. mediocolic s. a physiological s. located midway in the ascending colon. microscopic s. a s. visible only under the microscope. midgastric transverse s. SYN: s. angularis. midsigmoid s. the physiologic s. midway in the sigmoid colon. SYN: iliopelvic s.. muscular s. supracollicularis SYN: internal urethral s.. myovascular s. a s. having a muscular and a vascular (usually venous) component. See myovenous s.. myovenous s. a s. having a muscular and a venous component, e.g., at the pharyngoesophageal junction and anal canal. Nélaton s. See transverse folds of rectum, under fold. SYN: Nélaton fibers. O'Beirne s. SYN: rectosigmoid s.. s. oculi SYN: orbicularis oculi (muscle). Oddi s. SYN: s. of hepatopancreatic ampulla. s. oris SYN: orbicularis oris (muscle). ostial s. a thickening of circular muscular fibers at the level of an orifice. palatopharyngeal s. posterior fascicle of palatopharyngeus muscle. pancreatic s. SYN: s. of pancreatic duct. s. of pancreatic duct [TA] smooth muscle s. of the main pancreatic duct immediately proximal to the hepatoduodenal ampulla. SYN: musculus s. ductus pancreatici, pancreatic s., s. muscle of pancreatic duct. pathologic s. a thickening of circular musculature caused by disease. pelvirectal s. SYN: rectosigmoid s.. s. of the pharyngeal isthmus SYN: posterior fascicle of palatopharyngeus muscle. physiologic s. a section of a tubular structure that acts as if it has a band of circular muscle to constrict it, although no such specialized structure can be found on morphologic examination. SYN: functional s., radiologic s.. postpyloric s. the duodenal portion of the s. or closing mechanism of the gastroduodenal pylorus. prepapillary s. a s. of duodenum described in the location oral to the major duodenal papilla. preprostate urethral s. SYN: internal urethral s.. preprostatic s. internal urethral s.. prepyloric s. a band of circular muscular fibers in the wall of the stomach near the gastroduodenal pylorus. proximal urethral s. SYN: internal urethral s.. s. pupillae [TA] a ring of smooth muscle fibers surrounding the pupillary border of the iris. SYN: musculus s. pupillae [TA] , s. muscle of pupil. pyloric s. [TA] a thickening of the circular layer of the gastric musculature encircling the gastroduodenal junction. SYN: musculus s. pylori [TA] , s. muscle of pylorus. radiologic s. SYN: physiologic s.. rectosigmoid s. a circular band of muscular fibers at the rectosigmoid junction. SYN: O'Beirne s., O'Beirne valve, pelvirectal s.. segmental s. a s. of a segment of an organ, a tube, or a canal, and longer than an annular s.. smooth muscular s. SYN: lissosphincter. striated muscular s. SYN: rhabdosphincter. superior esophageal s. SYN: inferior constrictor (muscle) of pharynx. See inferior constrictor (muscle) of pharynx. supracollicular s. internal urethral s.. s. of third portion of duodenum a physiologic s. supposedly located at the horizontal (inferior) portion of the duodenum. unicanalicular s. a s. limited to one visceral canal or tube. s. urethrae externus [TA] SYN: external urethral s.. urethrovaginal s. [TA] voluntary, bandlike part of external urethral s. of female that encircles both urethra and vagina superior to the perineal membrane. SYN: musculus s. urethrovaginalis [TA] . s. vaginae SYN: bulbospongiosus (muscle). Varolius s. SYN: ileal s.. velopharyngeal s. SYN: posterior fascicle of palatopharyngeus muscle. s. vesicae SYN: internal urethral s.. s. vesicae biliaris the s. of the gallbladder, at the transition between the neck of the gallbladder and the cystic duct.

sphincteral (sfingk′ter-al)
Relating to a sphincter. SYN: sphincterial, sphincteric.

sphincteralgia (sfingk-ter-al′je-a)
Pain in the sphincter ani muscles. [sphincter + G. algos, pain]

sphincterectomy (sfingk-ter-ek′to-me)
1. Excision of a portion of the pupillary border of the iris. 2. Dissecting away any sphincter muscle. [sphincter + G. ektome, excision]

sphincterial, sphincteric (sfingk-ter′e-al, -ter-ik)
SYN: sphincteral.

sphincterismus (sfingk-ter-iz′mus)
Spasmodic contraction of the sphincter ani muscles.

sphincteritis (sfingk′ter-i′tis)
Inflammation of any sphincter.

sphincteroid (sfingk′ter-oyd)
Denoting similarity to a musculus sphincter. [sphincter + G. eidos, resemblance]

sphincterolysis (sfingk-ter-ol′i-sis)
An operation for freeing the iris from the cornea in anterior synechia involving only the pupillary border. [sphincter, + G. lysis, loosening]

sphincteroplasty (sfingk′ter-o-plas-te)
Operation on any sphincteric muscle. [sphincter + G. plastos, formed]

sphincteroscope (sfingk′ter-o-skop)
A speculum to facilitate inspection of the internal sphincter ani muscle. [sphincter + G. skopeo, to view]

sphincteroscopy (sfingk′ter-os′ko-pe)
Visual examination of a sphincter.

sphincterotome (sfingk′ter-o-tom)
An instrument for incising a sphincter.

sphincterotomy (sfingk-te-rot′o-me)
Incision or division of a sphincter muscle. [sphincter + G. tome, incision] external s. transurethral incision of external urethral sphincter. transduodenal s. division of Oddi sphincter; an operation to open the lower end of the common duct to remove impacted stones or to relieve spasm or stricture of the terminal bile and pancreatic ducts.

sphinganine (sfing′ga-nen)
Dihydrosphingosine;a constituent of the sphingolipids.

sphingol (sfing′gol)
SYN: sphingosine.

sphingolipid (sfing′go-lip-id)
Any lipid containing a long-chain base like that of sphingosine ( e.g., ceramides, cerebrosides, gangliosides, sphingomyelins); a constituent of nerve tissue.

sphingolipidosis (sfing′go-lip-i-do′sis)
Collective designation for a variety of diseases characterized by abnormal sphingolipid metabolism, e.g., gangliosidosis, Gaucher disease, Niemann-Pick disease. SYN: sphingolipodystrophy. cerebral s. any one of a group of inherited diseases characterized by failure to thrive, hypertonicity, progressive spastic paralysis, loss of vision and occurrence of blindness, usually with macular degeneration and optic atrophy, convulsions, and mental deterioration; associated with abnormal storage of sphingomyelin and related lipids in the brain. Four types are recognized as clinically and enzymatically distinct: 1) infantile type (Tay-Sachs disease, GM2 gangliosidosis) due to a deficiency of hexosaminidase A; 2) early juvenile type (Jansky-Bielschowsky or Bielschowsky disease); 3) late juvenile type (Spielmeyer-Vogt disease; Spielmeyer-Sjögren disease; Batten-Mayou disease; ceroid lipofuscinosis); and 4) adult type (Kufs disease). SYN: cerebral lipidosis.

sphingolipodystrophy (sfing′go-lip-o-dis′tro-fe)
SYN: sphingolipidosis.

sphingomyelinase (sfing′go-mi′e-li-nas)
SYN: sphingomyelin phosphodiesterase.

sphingomyelin phosphodiesterase (sfing′go-mi′e-lin)
An enzyme catalyzing hydrolysis of sphingomyelin to N-acylsphingosine (a ceramide) and phosphocholine; a deficiency of this enzyme is associated with type I Niemann-Pick disease. SYN: sphingomyelinase.

sphingomyelins (sfing′go-mi′e-linz)
A group of phospholipids, found in brain, spinal cord, kidney, and egg yolk, containing 1-phosphocholine (choline O-phosphate) combined with a ceramide (a long-chain fatty acid linked to the nitrogen of a long-chain base, such as sphingosine). SYN: ceramide 1-phosphorylcholine, phosphosphingosides.

sphingosine (sfing′go-sen)
The principal long-chain base found in sphingolipids. SYN: (4E)-sphingenine, sphingol.

See sphygmo-.

sphygmic (sfig′mik)
Relating to the pulse.

sphygmo-, sphygm-
Pulse. [G. sphygmos]

sphygmocardiograph (sfig′mo-kar′de-o-graf)
A polygraph recording both the heartbeat and the radial pulse. SYN: sphygmocardioscope. [sphygmo- + G. kardia, heart, + grapho, to write]

sphygmocardioscope (sfig′mo-kar′de-o-skop)
SYN: sphygmocardiograph. [sphygmo- + G. skopeo, to view]

sphygmochronograph (sfig′mo-kron′o-graf)
A modified sphygmograph that represents graphically the time relations between the beat of the heart and the pulse; one recording the character of the pulse as well as its rapidity. [sphygmo- + G. chronos, time, + grapho, to write]


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