# sphincter

/ˈsfɪŋktɝ/ (US) · /sfˈɪŋktɐ/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/sphincter
Updated: 2026-05-28

## Definition

a ring of muscle that opens and closes to control the flow of things through a tube in your body. It helps you control when you go to the bathroom.

For teachers: a ring of muscle that contracts and relaxes to control the flow of substances through a tube or opening in the body. Often used in medical contexts to describe the muscles of the digestive or urinary tracts.

## Examples

- The doctor checked the patient's sphincter for any signs of damage.
- After the surgery, the patient needed physical therapy to help the muscles of the sphincter regain their strength and control.
- The internal anal sphincter remains in a constant state of contraction, providing involuntary control, while the external sphincter allows for voluntary release of waste.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.