Cranial Nerves

CN I Olfactory Nerve (Sensory)

Sensory fibers from nasal mucosa for smell

Neurons in nasal cavity

Axons project superiorly through cribriform/olfactory foramina in ethmoid bone

CN II Optic Nerve (Sensory)

Sensory fibers from retina for vision

Wrapped by meninges

Runs in optic canal with ophthalmic artery

CN III Oculomotor (Motor)

Motor to extraocular muscles, parasympathetic

Emerges from brainstem → cavernous sinus → superior orbital fissure

Nuclei in midbrain (III and IV)

CN IV Trochlear (Motor)

Motor to superior oblique

Pons

Emerges from brainstem → cavernous sinus → superior orbital fissure

CN VI Abducens (Motor)

Motor to lateral rectus

Midbrain (III, IV)

Emerges from brainstem → cavernous sinus → superior orbital fissure

CN V1 Ophthalmic Nerve (Branch of CN V- Both)

Exits brain stem on lateral pons with all of CN V

Moves through cavernous sinus

Enters orbit through superior orbital fissure

Sensory

3 branches- nasociliary (anterior & posterior ethmoidal, infratrochear, long ciliary nn.), frontal (supraorbital, supratrochlear nn.), lacrimal

CN V2 Maxillary Nerve (Branch of CN V-Both)

Exits brain stem on lateral pons with all of CN V

Moves through cavernous sinus

Exits cranial cavity through foramen rotundum

Sensory- only from meninges, the maxillary sinus, nasal cavity mucosa, nasopharyngeal mucosa, palate, upper teeth, and skin of the midface

CN V3 Mandibular Nerve (Branch of CN V-Both)

Exits brain stem on lateral pons with all of CN V

Exits cranial cavity through foramen ovale

MOTOR to mm. of mastication, anterior digastric m., mylohyoid m., TVP, TTymp

SENSORY from meninges, skin of lower face & parotid region, TMJ & ear canal, lower teeth,

anterior 2/3 tongue (not taste)

CN VII Facial Nerve (Both)

Exits the brain stem at the pontomedullary junction

Exits cranial cavity at the internal auditory meatus

MOTOR to mm. of facial expression,

post. digastric, stylohyoid, and stapedius mm.

Parasymp MOTOR to lacrimal, nasal,

sublingual, and submandibular glands

SENSORY from ear canal

Special SENSORY for taste

from the anterior 2/3 tongue

CN VIII Vestibulocochlear (Sensory)

Exits the brain stem at the pontomedullary junction

Exits cranial cavity at the internal auditory meatus

SENSORY only

vestibulo- portion for balance

cochlear portion for hearing

CN IX Glossopharyngeal (Both)

- Exits the brain stem at the postolivary sulcus

in the medulla

→ Exits cranial cavity at the jugular foramen

→ MOTOR to stylopharyngeus m.

→ Parasymp MOTOR to parotid gland

→ SENSORY from the post. tongue, oropharynx,

palatine tonsils; carotid sinus & carotid body

→ Special SENSORY for taste from the

posterior 1/3 tongue

CN X Vagus (Both)

• - Exits the brain stem at the postolivary sulcus

in the medulla

→ Exits cranial cavity at the jugular foramen

→ MOTOR to salpingopharyngeus, lev. veli

palatini, palatoglossus, laryngeal mm.,

pharyngeal constrictor mm.

→ Parasymp MOTOR to glands of the larynx,

heart, lungs, GI tract to mid-transv. colon

→ SENSORY from external ear,

meninges of post. cranial fossa,

mucosa of the larynx,

laryngopharynx; heart, lungs,

esophagus, GI tract to

mid-transv. colon

→ Special SENSORY for

taste from the

epiglottic region

CN XI Accessory (Motor)

Exits the brain stem at the postolivary sulcus in the medulla

Exits cranial cavity at the jugular foramen

MOTOR to trapezius and sternocleidomastoid mm.

CN XII Hypoglossal (Motor)

Exits the brain stem at the preolivary sulcus in

the medulla

Exits cranial cavity at the hypoglossal foramen

MOTOR to tongue mm. (genioglossus,

hyoglossus, styloglossus, intrinsic mm.

Ethmoidal foramina

Exit point for CN I

Optic Canal

Exit point for CN II

Superior Orbital Fissure

Exit point for CN III, IV, VI + CN V1 (Ophthalmic)

Foramen Rotundum

Exit point for CN V2 Maxillary

Foramen Ovale

Exit point for CN V3 Mandibular

Internal Acoustic Meatus

Exit point for CN VII and CN VIII

Jugular Foramen

Exit point for CN IX, X, XI

Hypoglossal Canal

Exit point for CN XII

CN I Pathway

Olfactory bulb → cribriform plate → ethmoidal foramina

CN II Pathway

Optic chiasm → optical canal to cranial cavity

CN III Pathway

Interpeduncular fossa of midbrain → posterior cranial fossa → middle cranial fossa → cavernous sinus → superior orbital fissure

CN IV Pathway

Posterior surface of midbrain → dorsal midbrain → medial edge of tentorium → middle cranial fossa → cavernous sinus → superior orbital fissure

CN V Pathway

Pons → anterolateral pons into posterior cranial fossa → middle cranial fossa → CNV1 superior orbital fissure, CNV2 foramen rotundum, CNV3 foramen ovale

CN VI Pathway

Medullaopotine surface, medial to CN VII → exits between pons and medulla → superior orbital fissure

CN VII Pathway

Exits laterally between pons and medulla → internal acoustic meatus → stylomastoid foramen

CN VIII Pathway

Medullapotine sulcus, lateral to CN VII → exits brainstem between pons and medulla → internal acoustic meatus

CN IX

Retro-olivary groove of medulla → exits cranial cavity at jugular foramen → ganglia inf. to jugular foramen → inn. stylopharyngeus → branch into posterior oral cavity deep to hyoglossus → branch enters pharynx

CN X

Retro-olivary groove of medulla → exits cranial cavity at jugular foramen → runs between ICA and IJV → hella branches