Cranial Nerves

Cranial Nerves: Origin

12 pairs; 10 originate in the brainstem; numbered anterior to posterior.

CN I: Olfactory Nerve (Function)

Special Sensory: Smell (Olfaction).

CN I: Olfactory Nerve (Skull Passageway)

cribriform plate foramina and synapses in the olfactory bulbs

CN II: Optic Nerve (Function)

Special Sensory: Vision.

CN II: Optic Nerve (Skull Passageway)

Optic Canal

CN III: Oculomotor Nerve (Somatic Motor) responsible for 4/6 eye muscles:

Superior, Inferior, and Medial rectus; Inferior oblique

CN III: Oculomotor Nerve (2) Functions

somatic motor (controls 4/6 extrinsic eye muscles) and visceral motor (elevating the upper eyelid and managing pupil constriction)

CN III: Oculomotor Nerve (Ganglion)

Ciliary ganglion.

CN IV: Trochlear Nerve (Function)

Somatic Motor: Superior oblique eye muscle [depresses/moves down and abducts/moves outward eye].

CN IV: Trochlear Nerve (Skull Passageway)

superior orbital fissure

CN V: Trigeminal Nerve Somatic Sensory function

touch, temperature, and pain from the face

CN V: Trigeminal Nerve (Somatic (special) Motor) function

Muscles of mastication (chewing) [Mandibular division only!]

CN V: Trigeminal Nerve (Ganglion)

Trigeminal ganglion

CN VI: Abducens Nerve (Function)

Somatic Motor: Lateral rectus eye muscle (abducts/moves outward eye)

CN VII: Facial Nerve 5 functions

• “Expression, Taste, Moisture” nerve

• special sensory (taste from the anterior 2/3 of the tongue)

• visceral motor (lacrimal, sublingual, & submandibular glands)

• visceral sensory (sensory from above glands)

• somatic sensory (small area behind ear)

• somatic (special) motor [Posterior belly of the digastric, Stylohyoid, Stapedius muscles, Muscles of facial expression]

CN VII: Facial Nerve (Skull Passageway)

enters skull through the internal acoustic meatus, then branch to the facial muscles, and exits skull via the stylomastoid foramen

CN VII: Facial Nerve (Ganglia)

Pterygopalatine and Submandibular ganglia.

CN VIII: Vestibulocochlear Nerve (Function)

Special Sensory: Equilibrium (balance) and Hearing.

CN VIII: Vestibulocochlear Nerve (Skull Passageway)

Internal acoustic meatus

CN IX: Glossopharyngeal Nerve 5 functions

• for posterior tongue, throat (pharynx), and the parotid gland

• special sensory (taste from the posterior 1/3 of the tongue

• somatic sensory (pharynx)

• visceral sensory (carotid bodies, parotid gland)

• somatic (special) motor (stylopharyngeus)

• visceral motor (parotid gland)

CN IX: Glossopharyngeal Nerve (Skull Passageway)

Jugular foramen

CN IX: Glossopharyngeal Nerve (Ganglion)

Otic ganglion.

CN X: Vagus Nerve 5 functions

• ‘Big Boss of Visceral Control”

• special sensory (taste from base of the tongue, epiglottis,

  upper pharynx)

• somatic sensory (external acoustic meatus, eardrum, laryngopharynx, larynx)

• visceral sensory (heart, lungs, abdominal organs up to the first 2/3 of the transverse colon)

• somatic (special) motor (pharynx, larynx and

  palate muscles)

• visceral motor (heart, pharynx, larynx, trachea, lungs, abdominal organs up to 1st 2/3 transverse colon)

CN X: Vagus Nerve (Skull Passageway)

Jugular foramen

CN XI: Accessory Nerve (Function)

Somatic (Special) Motor: Trapezius and Sternocleidomastoid muscles (neck)

CN XI: Accessory Nerve (Skull Passageway)

Jugular foramen

CN XII: Hypoglossal Nerve (Function)

Somatic Motor: Intrinsic and extrinsic muscles of the tongue.

CN XII: Hypoglossal Nerve (Skull passageway)

hypoglossal canal

Cranial Nerves with Parasympathetic Fibers

• CN III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus)

• Mnemonic: 1973 - 10, 9, 7, 3