The Cranial Nerves

Overview of Cranial Nerves

• There are 12 pairs of cranial nerves.

• These nerves innervate the periphery and emerge directly from the brain (not from the spinal cord).

• The cranial nerves are located on the ventrolateral surface of the brain.

• They are numbered starting from the anterior aspect of the brain as follows:

  • CN I to CN XII

Mnemonic Devices for Cranial Nerves

Various Mnemonics for Remembering Cranial Nerves:

1. Orange Oregon O-lineman Tried Track And Field, Victory Gave Virginia School Honor

2. On Occasion Our Trusty Truck Acts Funny, Very Good Vehicle Any How

3. Once One Openly Told Tourists About Fighting Vampires Gobling Various Antelope Herds

4. On Old Olympus' Towering Top, A Friendly Viking Grew Vines And Hops

5. Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly.

6. Oh, Oh, Oh, To Touch And Feel Very Good' Velvet Aah Hah

7. Oh, Oh, Oh, To Touch And Feel Very Good Vibes AHhhh

8. One Of Old Trained Teacher Ask For A Girl Vadai And Halva

9. Oh, Oh, Oh, To Touch And Fondle A Gorgeous Very Super Human

10. Oh, Oh, Oh, To Touch And Feel Very Green Vegetables, Such Heaven

11. Oh, Oh, Oh, To Take A Family Vacation! Go Vegas After Hours

12. Only Owls Observe Them Traveling And Finding Voldemort Guarding Very Secret Horcruxes

13. Old Opie Occasionally Tries Trigonometry And Feels Very Gloomy, Vague And Hypoactive

14. Old Oprah Occasionally Trots Triumphantly About, Farting Velveeta Globs, Vaunting Accolades Hysterically

15. Oh, Oh, Oh, To Touch And Feel Vintage Green Velvet, Simply Heaven

16. Old, Oliver, Ogg, Traveled, To, Africa, For, Very, Good, Vacations, And, Holidays

17. Once On October Thirteenth, Troublesome Abductors Filched Various Golden Valuables And Heirlooms

18. Oprah Ought Order Tasty Treats And Finally Value Growing Voluptuous And Happy

19. Old Officers Often Trust The Army For A Glory Vague And Hypothetical

20. Old Oppressive Oceanic Trout Trick Aquatic Fauna Very Greedily; Valiant Sharks Hunt (them).

Detailed List of Cranial Nerves

CN I: Olfactory Nerve

• Function: Sensory (smell)

• Origin: Olfactory epithelium

• Foramen: Olfactory foramina

• Destination: Olfactory bulbs

CN II: Optic Nerve

• Function: Sensory (vision)

• Origin: Retina

• Foramen: Optic canal

• Destination: Diencephalon, then to occipital lobe

CN III: Oculomotor Nerve

• Function: Controls extra-ocular eye muscles (motor function)

  • Muscles controlled: Superior, inferior, medial rectus, inferior oblique

  • Levator palpebrae superioris

• Origin: Mesencephalon

• Foramen: Superior orbital fissure

• Destination: Extra-ocular eye muscles

CN IV: Trochlear Nerve

• Function: Controls the superior oblique muscle (motor function)

• Origin: Mesencephalon

• Foramen: Superior orbital fissure

• Destination: Superior oblique muscle

CN V: Trigeminal Nerve

• Function: Mixed (sensory and motor)

  • Sensory: Touch, pain, temperature, vibration from the anterior 2/3rds of the tongue.

  • Ophthalmic: Sensations from forehead, eyelids, and nose.

  • Maxillary: Sensations from lower eyelid, upper lip, and cheek.

  • Mandibular: Controls mastication.

• Origin: Ophthalmic, maxillary, and mandibular nerves

• Foramina:

  • Ophthalmic: Superior orbital fissure

  • Maxillary: Foramen rotundum

  • Mandibular: Foramen ovale

• Destination:

  • Ophthalmic and maxillary: Pons

  • Mandibular: Mandibular muscles

CN VI: Abducens Nerve

• Function: Controls eye movements (motor function)

• Origin: Pons

• Foramen: Superior orbital fissure

• Destination: Innervates the lateral rectus muscle

CN VII: Facial Nerve

• Function: Mixed (sensory and motor)

  • Sensory: Taste from anterior 2/3rds of tongue.

  • Motor: Muscles of facial expression

• Origin: Sensory from taste buds, motor from pons

• Foramen: Internal acoustic meatus to the stylomastoid foramen

• Destination: Sensory to pons, motor to muscles of the face, lacrimal gland, parasympathetic to submandibular and sublingual salivary glands

CN VIII: Vestibulocochlear Nerve

• Function: Sensory (balance and hearing)

• Origin: Receptors of the vestibule and cochlea

• Foramen: Internal acoustic meatus

• Destination: Pons

CN IX: Glossopharyngeal Nerve

• Function: Mixed (sensory and motor)

  • Sensory function: Tongue pain from posterior 1/3 of the tongue.

  • Motor function: Swallowing

• Origin: Sensory from posterior 1/3 of the tongue, motor from the parotid gland and parasympathetic to salivary gland

• Foramen: Jugular foramen

• Destination: Sensory to medulla oblongata, visceral motor to the parotid salivary gland, somatic motor to pharyngeal muscles for swallowing

CN X: Vagus Nerve

• Function: Mixed (sensory and motor)

  • Sensory: Information from organs

  • Motor: Sends information to organs

• Origin: Sensory from the organs, motor from medulla oblongata

• Foramen: Jugular foramen

• Destination: Sensory to the autonomic centers of the medulla oblongata, somatic motor to muscles of the palate and pharynx, visceral motor to respiratory, cardiovascular, and digestive organs

CN XI: Accessory Nerve

• Function: Motor function controlling the sternocleidomastoid, trapezius, palate, pharynx, and larynx muscles

• Origin: Spinal cord and medulla oblongata

• Foramen: Jugular foramen

• Destination: Internal branch to muscles of the palate, pharynx, larynx; external branch to sternocleidomastoid and trapezius muscles

CN XII: Hypoglossal Nerve

• Function: Motor, controls tongue movement

• Origin: Medulla oblongata

• Foramen: Hypoglossal canal

• Destination: Tongue muscles

Summary of Cranial Nerve Functions

Cranial Reflexes

Table 16.13: Reflexes Related to Cranial Nerves