Definition

1. Noun:
   • A muscle that extends or straightens a limb or body part: An extensor is a skeletal muscle that, when it contracts, causes the straightening or extension of a joint, increasing the angle between connected bones. It typically works in opposition to a flexor muscle.

Usage Examples

• Noun:
  • The quadriceps is a powerful extensor of the knee. (The quadriceps muscle group is responsible for straightening the leg at the knee joint.)
  • Damage to the radial nerve can weaken the extensor muscles in the forearm. (Injury to this nerve can impair the muscles that straighten the wrist and fingers.)

Advanced Usage

• Anatomical Terminology: Often used in compound anatomical names to specify a muscle's primary action.
  • The extensor digitorum muscle extends the fingers. (This specific muscle is named for its action of straightening the fingers.)
• Clinical Context: Used to describe conditions, injuries, or exercises related to these muscles.
  • The physical therapist recommended extensor strengthening exercises for her lower back. (The exercises are designed to strengthen the muscles that help straighten the spine.)

Variants and Related Words

• Extension (n): The act of straightening or the state of being straight. The movement produced by an extensor muscle.
  • Full extension of the elbow is necessary for many daily activities.
• Extensor Digitorum (n phrase): A specific muscle in the forearm that extends the fingers.
• Extensor Hallucis Longus (n phrase): A specific muscle in the leg that extends the big toe.

Synonyms

• Antigravity muscle: (In some contexts, especially for leg extensors) A muscle that works against gravity to maintain posture.
• Note: There is no perfect single-word synonym. "Extensor" is a precise anatomical term.

Related Phrases

• Extensor mechanism: (Technical phrase) The combined structures (muscles, tendons, ligaments) that work together to extend a joint, such as the knee.
  • The patella is a key part of the knee's extensor mechanism.
• Extensor tendon: The tendon that connects an extensor muscle to a bone.
  • He suffered a laceration to an extensor tendon on the back of his hand.

Noun

1. a skeletal muscle whose contraction extends or stretches a body part