sphincter /sphinc·ter/ (sfingk´ter) [L.] a ringlike muscle which closes a natural orifice or passage.sphinc´teralsphincter´ic
Sphincter
sphincter
sphincter (sfingk´t
r),
anal sphincter , sphincter a´ni sphincter muscle of anus (external or internal).
cardiac sphincter , cardioesophageal sphincter muscle fibers about the opening of the esophagus into the stomach.
external sphincter of female urethra external sphincter muscle of female urethra.
external sphincter of male urethra external sphincter muscle of male urethra.
gastroesophageal sphincter the terminal few centimeters of the esophagus, which prevents reflux of gastric contents into the esophagus.
hepatic sphincter a thickened portion of the muscular coat of the hepatic veins near their entrance into the inferior vena cava.
internal sphincter of urethra internal sphincter muscle of urethra.
O'Beirne's sphincter a band of muscle at the junction of the sigmoid colon and rectum.
sphincter of Oddi the sheath of muscle fibers investing the associated bile and pancreatic passages as they traverse the wall of the duodenum.
pharyngoesophageal sphincter a region of higher muscular tone at the junction of the pharynx and esophagus, which is involved in movements of swallowing.
precapillary sphincter a smooth muscle fiber encircling a true capillary where it originates from the arterial capillary, which can open and close the capillary entrance.
pyloric sphincter see under muscle.
rectal sphincter an incomplete band or thickening of the muscle fibers in the rectum a few inches above the anus in the upper part of the rectal ampulla.
tubal sphincter an encircling band of muscle fibers at the junction of the uterine tube and the uterus.
vesical sphincter internal sphincter muscle of urethra.
sphinc·ter (sf ngk t r)n. A ringlike muscle that normally maintains constriction of a body passage or orifice and that relaxes as required by normal physiological functioning. Also called anatomical sphincter. sphinc ter·al, sphinc·teric (-t rk) adj. |
Sphincter
A circular band of muscle that surrounds and encloses an opening to the body or to one of its hollow organs. Damage to the sphincter surrounding the anus can cause fecal incontinence.
Mentioned in: Cystometry, External Sphincter Electromyography, Fecal Incontinence, Neurogenic Bladder, Overactive Bladder, Paruresis
sphincter
[sfingk′tər]
Etymology: Gk, sphingein, to bind
a circular band of muscle fibers that constricts a passage or closes a natural opening in the body, such as the hepatic sphincter in the muscular coat of the hepatic veins near their union with the superior vena cava, and the external anal sphincter, which closes the anus.
sphincter (sfingk´t
r),n a circular band of muscle fibers that constricts a passage or closes a natural opening in the body.
sphincter
a circular muscle that constricts a passage or closes a natural orifice. When relaxed, a sphincter allows materials to pass through the opening. When contracted, it closes the opening. The principal abnormalities relate to function. Failure to open may be because of spasm or achalasia, due usually to failure of parasympathetic nerve supply. Failure to close usually due to absence of sympathetic nerve supply. The important sphincters are the anal, ileal, pharyngoesophageal, pupillary, pyloric, reticulo-omasal, teat, urethral, vaginal and vesical.
cardiac sphincter
the functional sphincter at the gastric end of the esophagus.
sphincter control
is by the autonomic nervous system.
esophageal sphincter
see cardiac sphincter.
sphincter of Oddi
bile duct sphincter.
pupillary sphincter
a ring of smooth muscle around the pupillary border of the iris.
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