• WordNet 3.6
    • n sphincter a ring of muscle that contracts to close an opening
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Webster's Revised Unabridged Dictionary
    • n Sphincter (Anat) A muscle which surrounds, and by its contraction tends to close, a natural opening; as, the sphincter of the bladder.
    • a Sphincter (Anat) Of, pertaining to, or designating, a sphincter; as, a sphincter muscle.
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Century Dictionary and Cyclopedia
    • n sphincter An orbicular, circular, or annular muscle surrounding and capable of closing a natural orifice or passage of the body.
    • n sphincter The sphincter ani proper, sphincter externus, or external sphincter is a thin, flat plane of voluntary muscular fibers supplied by hemorrhoidal branches of nerves from the sacral plexus, surrounding the anus, subcutaneous and intimately adherent to the integument, of elliptical form 3 or 4 inches in long diameter, and an inch wide across. It arises from the tip of the coccyx, and is inserted into the tendinous raphe of the perineum. Like most sphincters. it consists of symmetrical lateral halves united by a raphe in front of and behind the opening it incloses.
    • n sphincter The sphincter recti, sphincter internus, or internal sphincter surrounds the lower end of the rectum, forming a muscular ring about an inch in extent and a quarter of an inch thick, and consists of an aggregation and thickening of the circular fibers of the gut. This sphincter is involuntary, and in health maintains its tonic contractility, which yields by reflex action to the pressure of the contents of the bowel.
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Chambers's Twentieth Century Dictionary
    • n Sphincter sfingk′tėr (anat.) a muscle that contracts or shuts an orifice or opening which it surrounds—around the anus, &c
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  • Matthew Green
    Matthew Green
    “Avarice is the sphincter of the heart.”


Webster's Revised Unabridged Dictionary
NL., fr. to bind tight
Chambers's Twentieth Century Dictionary
Gr. sphingktēr,—sphinggein, to bind tight.


In literature:

The sphincters were unaffected.
"Anomalies and Curiosities of Medicine" by George M. Gould
On what principle could a piece of chocolate inhibit the call to stool or contract the sphincter muscle?
"Outwitting Our Nerves" by Josephine A. Jackson and Helen M. Salisbury
Thus a horse voids his excrement when its weight or bulk irritates the rectum or sphincter ani.
"Zoonomia, Vol. I" by Erasmus Darwin
Finally the pupils dilate, the sphincters relax, and death ensues.
"Manual of Surgery" by Alexis Thomson and Alexander Miles
The symptoms of this condition are fighting for breath, giddiness, relaxation of the sphincters, and convulsions.
"Aids to Forensic Medicine and Toxicology" by W. G. Aitchison Robertson
They also had triangular-shaped mouths which worked somewhat on the sphincter method.
"Man of Many Minds" by E. Everett Evans
The valve at the anus, which retains the faeces, is another instance of a sphincter.
"Text Book of Biology, Part 1: Vertebrata" by H. G. Wells
In connection with this it may be noted that frequently there is paralysis of the sphincter ani and a dilated condition of the anus.
"Special Report on Diseases of the Horse" by United States Department of Agriculture
P. The sphincter ani muscle.
"Surgical Anatomy" by Joseph Maclise
The rectal muscular fibres perform the office of a sphincter for the sigmoid cavity.
"Intestinal Ills" by Alcinous Burton Jamison
He watched her as she crossed the recreation room floor and stepped through the exit sphincter.
"Starman's Quest" by Robert Silverberg
As in the furor uterinus, and satyriasis, and in the sphincter ani and scrotum.
"Zoonomia, Vol. II" by Erasmus Darwin
Introduce the bulb of an ordinary clinical thermometer, well greased with vaseline, just within the sphincter ani.
"The Elements of Bacteriological Technique" by John William Henry Eyre
The urethra and anal canal are insensitive, and there is paralysis of the levatores ani, the rectal and the vesical sphincters.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition." by Alexander Miles
The fleshy fibres on each side of this opening act as a sphincter.
"Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4" by Various
Upon examination the sphincter muscle which closes the anus of the female when stretched will be found to have a folded appearance.
"Ducks and Geese" by Harry M. Lamon
Perry heard Ada going crazy in the kitchen with a mechanical sphincter he'd been building.
"Makers" by Cory Doctorow
The sphincter was tight, grasped the finger with the usual firmness, and there were no sources of irritation about the anus.
"Degeneracy" by Eugene S. Talbot
In some cases the invaginated gut may be felt protruding through the sphincter.
"Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 6" by Various
If the nates present, the state of the sphincter ani will be a sure guide in ascertaining whether the child be alive or not.
"A System of Midwifery" by Edward Rigby

In news:

Faecal incontinence is usually attributed to pelvic-floor denervation of striated muscle or direct sphincter trauma.
Bile is a digestive fluid secreted by the liver and stored in the gallbladder which normally is released into the duodenum portion of the small intestine through the sphincter of Oddi.
Visual Arts Picasso drew and painted plenty of sphincters in his perverse erotic fantasias, but the necessary but generally unglamorous muscle doesn't get a lot of face time in fine art—not even in nudes.
Faecal incontinence is usually attributed to pelvic-floor denervation of striated muscle or direct sphincter trauma.
Of late, I've gotten my gnarled and trembling fingers on some diverse and very good sporting equipment, so pucker your sphincters and grab your wallets.
Patulous lower esophageal sphincter.
Sphincter Tattoos – Another Sign that the End is Near.
Urinary continence is maintained by a muscular sphincter that surrounds the urethra as it exits the bladder.
A slide show explaining inflatable artificial sphincters.
Sphincters tighten spasmodically at the sound of the parasitic boss's voice.
Pelvic Floor Incontinence is the unwanted passage of stools in which women are unable to control their sphincter muscles when they eliminate waste.