In general, the peripheral nervous system can be considered the communication path between the central nervous system (CNS), the internal and external environment of the body. Peripheral nerves have three categories of nerve fibers, which include the following:Sensory;Movement;Mixed.In total, the peripheral nervous system can be considered 12 pairs of nerves leaving the brain and 31 pairs of spinal nerves. Those peripheral nerves that transmit information and data to the central nervous system are called sensory or afferent nerves, and those peripheral nerves that send commands from the brain and spinal cord to functional organs are called motor or efferent nerves.