sphincter

American  

[sfingk-ter] / ˈsfɪŋk tər /

noun

Anatomy.

1. a circular band of voluntary or involuntary muscle that encircles an orifice of the body or one of its hollow organs.

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sphincter British  

/ ˈsfɪŋktə /

noun

1. anatomy a ring of muscle surrounding the opening of a hollow organ or body and contracting to close it

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sphincter Scientific  

/ sfĭngk′tər /

1. A ring-shaped muscle that encircles an opening or passage in the body. The opening and closing of the anus is controlled by contraction and relaxation of a sphincter, as is the opening that leads to the stomach from the esophagus.

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Other Word Forms

• sphincteral adjective
• sphincterate adjective
• sphincterial adjective
• sphincteric adjective

Etymology

Origin of sphincter

1570–80; < Late Latin < Greek sphinktḗr, equivalent to sphing-, base of sphíngein to hold tight + -tēr suffix denoting agent

Example Sentences

The detrusor muscle of the bladder wall relaxes to allow the bladder to fill and empty, while the external sphincter opens when it's appropriate to allow urine to flow out, but otherwise keeps tightly shut.

From Science Daily

Reduced pressure on the urinary sphincter is one of the many sensations dulled by living in microgravity, along with smell, taste and sight.

From Salon

This can make your stomach produce more acid, and it can also relax the sphincter muscle between your stomach and esophagus, allowing stomach acid to back up into your esophagus.

From Seattle Times

Normally the swallowing tube ends with a tight sphincter that stays closed to protect delicate tissue from the harsh acid of the stomach.

From New York Times

"When you sneeze or cough, there is a mechanical pressure from your belly that overwhelms the sphincter and you leak," she said.

From Science Daily