Definition

1. Noun:
   • A medical condition involving involuntary muscular contractions and relaxations: Clonus is a neurological sign characterized by rapid, rhythmic, and involuntary muscle contractions and relaxations, typically in response to a sustained stretch. It is often associated with lesions in the upper motor neurons.

Usage Examples

• Noun:
  • The neurologist tested for ankle clonus by quickly dorsiflexing the patient's foot.
  • Persistent clonus is a strong indicator of a possible spinal cord injury.
  • The presence of clonus in the knee reflex suggested heightened reflex activity.

Advanced Usage

• "to elicit clonus": to trigger the rhythmic muscular contractions through a specific maneuver, such as a quick stretch.
  • The physician attempted to elicit clonus to assess the severity of the spasticity.
• "sustained clonus": clonus that continues for several beats or more, as opposed to a few brief contractions.
  • Sustained clonus of more than five beats is considered abnormal.
• "clonus vs. spasticity": used in medical discourse to differentiate between this specific rhythmic sign and the broader condition of increased muscle tone.
  • The examination revealed both spasticity and clonus in the lower limbs.

Variants and Related Words

• Clonic (adj): relating to or characterized by clonus or similar alternating movements.
  • The seizure had a clonic phase involving rhythmic jerking.
• Myoclonus (n): a brief, involuntary twitching of a muscle or group of muscles, distinct from the rhythmic nature of clonus.

Synonyms

• Rhythmic myoclonus: (in specific contexts) emphasizes the regular, oscillating pattern.
• Involuntary oscillatory contraction: a more descriptive, technical synonym.

Related Terms and Phrases

• Ankle clonus: the most commonly tested form, elicited at the ankle joint.
  • The test for ankle clonus was positive.
• Patellar clonus: clonus elicited at the knee by displacing the patella.
  • Patellar clonus is less common than ankle clonus.

Notes

• Clonus is not an idiom or a phrasal verb. It is a specialized medical term.
• It is primarily used as a noun. The related adjective is "clonic."

Noun

1. convulsion characterized by alternating contractions and relaxations