Sensory nerves bring information from the sensory receptor organs that receive information from the energy flux in the external environment or from the organs within the body.
The cranial nerves originate in sensory receptors or terminate in muscles or glands located in the head. Their location on the base of the brain are shown in the accompanying figure.

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The cranial nerves are usually identified by Roman numerals as follows:

• I: The Olfactory bulb and tract.
  

• II: The Optic nerve.
  

• III: The oculomotor nerve.
  

• IV: The trochlear nerve.
  

• V: The trigeminal nerve.
  

• VI: The abducent nerve.
  

• VII: The facial nerve.
  

• VIII: The vestibulocochlear nerve.
  

• IX: The glossopharyngeal nerve.
  

• X: The vagal nerve.
  

• XI: The accessory nerve.
  

• XII: The hypoglossal nerve.