Clonus Health Dictionary

A rapid series of abnormal muscle contractions that occur in response to stretching. Clonus is a sign of damage to nerve fibres that carry impulses from the motor cortex in the cerebrum to a particular muscle. It is also a feature of seizures in grand mal epilepsy.

A succession of intermittent muscular relaxations and contractions usually resulting from a sustained stretching stimulus. An example is the clonus stimulated in the calf muscle by maintaining sustained upward pressure on the sole of the foot. The condition is often a sign of disease in the brain or spinal cord.

n. rhythmical contraction of a muscle in response to a suddenly applied and then sustained stretch stimulus. It is most readily obtained at the ankle when the examiner bends the foot sharply upwards and then maintains an upward pressure on the sole. It is caused by an exaggeration of the stretch reflexes and is usually a sign of disease in the brain or spinal cord.