what is the difference between spasticity and clonus
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).
Think rigid. Rigidity is a condition of hardness, stiffness or inflexiblity. You find this with muscle contractures. Now think spastic. Spasticity is a form of muscular hypertoncity (excessive muscle tone) with increased resistance to stretching. It usually occurs in the flexor muscles of the arms and legs. You would see movement that requires greater effort and with a lack of control and coordination.