A nerve is like an electrical cable wrapped in insulation. Motor nerves carry messages from the brain to muscles to make the body move. Sensory nerves carry messages to the brain from different parts of the body to signal pain, pressure, and temperature.
Nerves are fragile and can be damaged by pressure, stretching, or cutting.
Injury to a nerve can stop signals to and from the brain causing muscles not to work right, and you may lose feeling in the injured area. When a nerve is cut, both the nerve and the insulation are broken. Pressure or stretching injuries can cause the fibers carrying the information to break and stop the nerve from working, without damaging the cover. When nerve fibers are cut, the end of the fiber farthest from the brain dies, while the insulation stays healthy. The end that is closest to the brain does not die, and after some time may begin to heal.