<prompt> According to Herrington classification the decerebrate rigidity is characterised by all EXCEPTRigidity occurs all muscles of the bodyIncreased in the rate of discharge of the y efferent neuronIncreased excitability of the motor neuron poolDecerebration produces no phenomenon akin to spinal shock  <response>: Rigidity occurs in all muscles of the body 210-11 Ganong 22nd 692- Guyton 11th 247- Ganong 23rdDECEREBRATE - RIGIDITY - When the brain stem of an animal is sectioned below the mid level of the mesencephalon. But the pontine and medullary reticular system as well as the vestibular system are left intact, the animal develops a condition called decerebrate rigidity This rigidity does not occur in all muscles of the body but does occur in the antigravity muscles - the muscles of the neck and trunk and the extensors of the leg. The cause of decerebrate rigidity is blockage of normally strong input to the medullary reticular nuclei from the cerebral cortex, the red nucleus and the basal ganglia. Lacking this input, the medullary reticular inhibitor system become non functional; Full overactivity of the pontine excitatory system occurs, and rigidity develops. Decerebrate rigidity is found to be spasticity due to diffuse facilitation of stretch reflexes The facilitation is due to two factors: increased general excitability of the motor neuron pool and increased in the rate of discharge in the y efferent neuron Decerebration produces no phenomenon akin to spinal shock. And the rigidity develops as soon as the brain stem is transected 