Illustration of the cranial nerves, 12 sets of nerves which connect the brain to the rest of the body. From anterior (front) to posterior (rear), these include: the olfactory nerves (red, I), optic nerves (indigo, II), oculomotor nerves (violet III), trochlear nerves (pink, IV), trigeminal nerves (orange, V), abducens nerves (brown VI), facial nerves (yellow, VII), vestibulocochlear nerves (green, VIII), glossopharyngeal nerves (bright green, IX), vagus nerves (pale green, X), accessory nerves (grey, XI), and hypoglossal nerves (blue, XII). The cranial nerves are broadly classed as either sensory, which detect and respond to external stimuli, motor, which are involved in muscle control, or both. For a labelled version see: F041/8448.