What is decorticating and decerebrating?

Two levels in coma. Decorticate rigidity occurs as the connection between the cortex of the brain and the rest of the nervous system is interrupted, when pressure is applied to the sternum arms flex and legs extend. Decerebration is a more advanced stage of coma when the connection is interrupted between the entire brain and the rest of the nervous system. The result is the extension of the 4 extremities.