A ring of muscle surrounding and serving to guard or close an opening or tube, such as the anus or the openings of the stomach.‘the anal sphincter’
- ‘This rapidly closes the duodenal sphincter to contain the stomach contents.’
- ‘It is girdled by the external anal sphincter, a striated muscle structure that is part of the pelvic floor musculature.’
- ‘This smooth muscle is the involuntary sphincter of the posterior urethra in the male.’
- ‘Anal manometry is performed to assess the anal sphincter, pelvic floor, and associated nerves.’
- ‘Then your brain tells your pelvic floor muscles to relax and your sphincter (the opening at the neck of your bladder) to open.’
Late 16th century via Latin from Greek sphinktēr, from sphingein ‘bind tight’.
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