cranial nerves

12 pairs of NERVES that arise directly from the BRAIN , each with dorsal and ventral branches known as roots. Each root remains separate and is assigned a Roman numeral as well as a name. Some cranial nerves are mainly SENSORY while others are largely MOTOR , and they leave the SKULL through separate apertures. The cranial and spinal nerves (see SPINAL CORD ) are an important part of the PERIPHERAL NERVOUS SYSTEM , which comprises all parts lying outside the brain and spinal cord.