cranial nerves

How to memorize the 12 cranial nerves without a mnemonic

  • Use a mnemonic (it’s not as difficult as they make it out to be; the tough part during medical school is memorizing their “route” which is similar to being asked to memorize map quest directions)
  • “Oh Oh Oh To Touch And Feel A Girls Very Soft Hands”  or try Trend finding for memorization where you assume that nerves of eyes come first + more important nerves are both sensory and motor (others are just sensory or just motor)
  • CN I or 1. Olfactory (nose sticks out farthest so it is CN I; does ONLY SMELL sensory)
  • CN II or 2. Optic (eyes stick out second farthest so it is CN II; does ONLY VISION sensory)
  • CN III or 3. Oculomotor (eye muscles are most inward so it is CN III; does ONLY MOVEMENT EYES motor)
  • CN IV or 4. Trochlear (“I soT for lArs” Superior oblique eye movement (covered later) by Trochlear SOT is first part of mnemonic so trochlear is CN IV: does ONLY MOVEMENT via superior oblique for EYES motor) 
  • CN V or 5. Trigeminal (The trigeminal nerve is an exception to the first nerves being only eye nerves but it does all the sensation of your face and has 3 parts CNVa (occipital), CNVb (maxillary), CNVc (mandibular) Part Vb and Vc also do motor so CN5 is BOTH sensory and motor!
  • CN VI or 6. Abducens (we are back in order! “I soT for lArs” second part of this phrase l and r stand for the muscle lateral rectus which the abducens nerve controls)
  • CN VII or 7: Facial: (CN 7 lucky number 7 is the nerve that gets to show facial expression of surprise when winning a jackpot!  Important nerve does both sensory and motor
  • CN VIII or 8: Vestibulocochlear (CN 8 travels with 7 so it must come right after in sequence; does cochlear = hearing vestibular = balance so only sensory
  • CN IX or 9: Glossopharyngeal (DONT MIX UP WITH CN XII HYPOGLOSSAL WHICH IS MOTOR ONLY; this tongue nerve (glosso=tongue) does both taste AND motor. Since Facial nerve also does some taste; it comes closely following the facial nerve.
  • CN X or 10: Vagus (the party starts at 10pm in vegas!; Vagus is a huge nerve so it does both motor and sensory). 
  • CN XI or 11: Spinal Accessory: We saw this nerve innervating spinal muscles and its similar to spinal (not cranial) nerves so it must be motor only and lower ranked on the stem. 
  • CN XII or 12: Hypoglossal: Tongue muscle nerve gets to be the last in the chain! It is just tongue muscles so motor only.