thumb|Ankle clonus

Clonus is a set of involuntary and rhythmic muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, particularly associated with upper motor neuron lesions involving descending motor pathways and, in many cases, is accompanied by spasticity (another form of hyperexcitability). It can also be an adverse drug reaction, such as after ingestion of potent serotonergic drugs, where clonus strongly predicts imminent serotonin toxicity (serotonin syndrome).

Mechanism

Hyperactive stretch reflexes

The self re-excitation of hyperactive stretch reflexes theory involves a repetitive contract-relax cycle in the affected muscle, which creates oscillatory movements in the affected limb.

In the text, Bateson goes on to describe induction of clonus as a key element of Balinese ritual.

See also

  • Myoclonus
  • Generalized tonic–clonic seizure
  • Stretch reflex
  • Tetany
  • Tetanic contractions

References

</references>

  • Dr. Gilman on Serotonin Toxicity
  • Video about Clonus at the ankle
  • Video about Clonus at the knee (patella)