Spastic quadriplegia, also known as spastic tetraplegia, is a subset of spastic cerebral palsy that affects all four limbs (both arms and legs). Compared to quadriplegia, spastic tetraplegia is defined by spasticity of the limbs as opposed to strict paralysis. It is distinguishable from other forms of cerebral palsy in that those afflicted with the condition display stiff, jerky movements stemming from hypertonia of the muscles.