How many sphincter are in human body

The short answer: About a dozen major named sphincters (roughly 12), but many more if you count small/physiological and microscopic sphincters.

Explanation

“Sphincter” means a circular muscle that closes or opens a passage. Which structures you count depends on your definition:

  • If you count the common, anatomically named sphincters used in clinical anatomy, you get about 12 major ones.
  • If you also count physiological sphincters (areas of tonic muscle without a distinct ring), ureteric/vesical valves, and the countless micro‑sphincters in blood vessel beds (precapillary sphincters), the total is much larger and not a single fixed number.

Commonly listed major sphincters (≈12)

  • Orbicularis oculi (eyelid sphincter)
  • Orbicularis oris (lip/mouth sphincter)
  • Sphincter pupillae (iris, constricts pupil)
  • Upper esophageal sphincter (cricopharyngeus)
  • Lower esophageal (cardiac) sphincter (physiologic LES)
  • Pyloric sphincter (stomach → duodenum)
  • Sphincter of Oddi (bile/pancreatic outflow)
  • Ileocecal valve (ileum → cecum)
  • Internal anal sphincter (smooth muscle)
  • External anal sphincter (skeletal muscle)
  • Internal urethral sphincter (bladder neck, mainly smooth)
  • External urethral sphincter (skeletal sphincter urethrae)

Note: anatomists/clinicians sometimes list additional sphincteric regions (ureterovesical junction, pelvic floor muscles like puborectalis acting as a sphincteric sling, precapillary sphincters in microcirculation), so counts vary.

If you want, I can:

  • Give a diagram or map showing these sphincters, or
  • List a longer set including physiological/microscopic sphincters and explain how each works. Which would you prefer?
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Related

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