The central nervous system (CNS) is made up of the brain, the spinal cord, and the optic nerves. The central nervous system controls thought processes, guides movement, and registers sensations throughout the body.

The spinal cord is a single continuous structure that goes from the brain through the base of the skull and down the spinal column. Individual paired spinal nerves continue down to the tailbone. The optic nerves are at the back of the eye and carry visual information from the eye to the brain.

Injuries or diseases that affect the central nervous system can sometimes cause permanent loss of function and disability.