Loss of the ability to move the muscles resulting from a disorder of the nervous system or of the muscles. Paralysis may be either temporary or permanent. The whole body can be paralyzed, although paralysis may affect only one part of the body, or only one muscle. Paralysis is either slack (chiefly as a result of neural conditions) or spastic (conditions of the spinal cord or brain), depending on the cause. In slack paralysis the muscles are limp and eventually atrophy. The motor nerves are affected, and in consequence the relevant muscles receive little or no stimulus. The causes are conditions such as spinal muscular atrophy or poliomyelitis. Disorders of the nerve roots of the spinal cord include slipped disc and the Guillain-Barre’ syndrome. Nerves can also be affected in the course of a disease, as in certain forms of neuritis or in the carpal tunnel syndrome. Slack paralysis can also occur in serious muscular disorders such as muscular dystrophy. The extent of the paralysis and the course of the disorder depend on the underlying cause. Treatment is also directed towards the cause. Physiotherapy is of importance in order to keep the muscles in optimum condition and to combat stiffening of the joints. Other aids can sometimes be useful. In spastic paralysis, loss of strength is accompanied by increased muscular tension. As a result of a disturbance in the brain or the spinal cord, the motor nerves are no longer inhibited. They are normally continuously active, but kept