anal sphincter

noun

: either of two sphincters controlling the closing of the anus:
a
: an outer sphincter of striated muscle extending from the coccyx to the central tendinous part of the perineum and surrounding the anus immediately beneath the skin

called also external anal sphincter, sphincter ani externus

b
: an inner sphincter formed by thickening of the circular smooth muscle of the rectum

called also internal anal sphincter, sphincter ani internus

Dictionary Entries Near anal sphincter

Cite this Entry

“Anal sphincter.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/anal%20sphincter. Accessed 9 Dec. 2022.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!


Commonly Confused Words Quiz

  • vector image of a face with thought expression
  • I went to the ______ store to buy a birthday card.
Spell It

Hear a word and type it out. How many can you get right?

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ