Definition

1. Noun:
   • The sphincter muscle of the anus: A ring of muscle surrounding and controlling the opening of the anus.

Usage

• The term "sphincter ani" is a specific anatomical term. It is used in medical, biological, and physiological contexts to refer precisely to this muscle. It is typically not used in everyday conversation.

Examples

• Noun:
  • The surgeon carefully repaired the damaged sphincter ani.
  • Control of defecation involves the voluntary and involuntary actions of the sphincter ani.

Advanced Usage

• "Sphincter ani externus": Refers specifically to the external anal sphincter, which is composed of skeletal muscle and is under voluntary control.
  • The sphincter ani externus is crucial for maintaining continence.
• "Sphincter ani internus": Refers specifically to the internal anal sphincter, which is composed of smooth muscle and is under involuntary control.
  • The tone of the sphincter ani internus is primarily regulated by the autonomic nervous system.

Variants and Related Words

• Anal sphincter (n): A more common clinical synonym for "sphincter ani."
  • The patient was diagnosed with a weakened anal sphincter.
• Sphincter (n): The general term for a circular muscle that constricts or closes an orifice.
  • The pyloric sphincter controls the passage of food from the stomach.

Synonyms

• Anal sphincter: The direct and most common synonym.
• Anorectal sphincter: A less common, more formal synonym.

Related Phrases

• Sphincter control: Refers to the ability to regulate the sphincter muscles.
  • The therapy aims to improve sphincter control after the injury.
• Sphincter injury: Damage to the sphincter muscle.
  • Childbirth can sometimes lead to a sphincter injury.

Noun

1. the sphincter muscle of the anus