Quadriplegia is when both of a person's arms and both legs stop working. It usually
happens because of an injury or disease that affects the
brain or spinal cord. The spinal
cord is a long bundle of nerves that goes from the lower part of the brain down through
the middle of the back. It carries messages from the brain to the rest of the body.
If the spinal cord is hurt, the messages stop getting where they need to go.