Spasticity involves the inability or difficulty to control involuntary muscle movements and rigidity involves the inability or difficulty to relax muscles after they’ve been shortened?

Spasticity and rigidity are properties of muscle tone. Muscle tone in hypertonia is describes as rigidity or spasticity. Spasticity is caused by damage to corticospinal tract and rigidity is caused by damage to extrapyramidal pathways. In spasticity muscle tone is very high, asymmetric and effects antagonizing muscle groups. Its visibility is dependent on velocity and amplitude of movement. It is short lived. Whereas, in rigidity the high tone is maintained through-out a movement. Rigidity is independent of velocity and is visible even on slow movements. Spasticity is seen in stroke, spinal cord compression and motor neuron disease. Rigidity is seen in Parkinson's disease and neuroleptic malignant syndrome..