Paralysis is a condition of the body in which muscles fail to function. It may be caused by a birth defect, by disease, or by tumor growth.
   Paralysis occurs in several ways. Since muscles react to stimuli from nerves originating in the brain or spinal cord, a disturbance or disability, of any of these parts brings about a condition of paralysis.
   Diseases of the BRAIN or SPINAL CORD prevent receiving, sorting, or sending stimuli to cause muscle reaction. Spinal MENINGITIS is an example of a disease caused by the inflammation of the spinal cord. In other types of paralysis, the nerves leading to or from the central nervous system have been disturbed so that they are incapable of transmitting stimuli as required. A third type of disability exists when the muscle cells themselves cannot perform normally.