Cranial Nerve

Overview of the Exits of the Cranial nerve

  • CN I → cribriform plate

  • CN II → optic canal

  • CN III → superior orbital fissure

  • CN IV → superior orbital fissure

  • CN V →

    • CN V1 → superior orbital fissure

    • CN V2 → foramen rotundum

    • CN V3 → foramen ovale

  • CN VI = superior orbital fissure

  • CN VII → internal acoustic meatus

  • CN VIII → internal acoustic meatus

  • CN IX → jugular foramen

  • CN X → jugular foramen

  • CN XI → jugular foramen

  • CN XII → hypoglossal canal

Acronym:

  • Some

  • Say

  • Marry

  • Money

  • But

  • My

  • Brother

  • Says

  • Big

  • Brains

  • Matter

  • More

Olfactory Nerve (I)

  • Function: smell from the nasal mucosa to the brain

  • Classification: Afferent

  • Location: cribriform plate of the ethmoid bone

Optic Nerve (II)

  • Function: sight from the retina to the brain

  • Classification: Afferent

  • Location: optic canal in the sphenoid bone

Oculomotor Nerve (III)

  • Function: movement of the eye muscle

  • Classification: Efferent

  • Location: superior orbital fissure of the sphenoid bone

Trochlear nerve (IV)

  • Function: the superior oblique muscle of the eye

  • Classification: Efferent

  • Location: superior orbital fissure of the sphenoid bone

Trigeminal Nerve (V)

  • Note: Largest cranial nerve and MOST significant due to innervation of tissue, structures, and organs of the head and neck

  • Three division: Ophthalmic V1, Maxillary V2, and Mandibular V3

    • both afferent and efferent

Division

Type

Function

Area Supplied

Illustration

Ophthalmic (V1)

Afferent

Eyes, skin of the forehead, eyelids, nose

superior orbital fissure

Maxillary (V2)

Afferent

Cheek, lower eyelid, nose, upper lip; all maxillary teeth

foramen rotundum

Mandibular (V3)

Afferent & Efferent

Sensory: pain, temperature, touch, and pressure (lower face, including mandibular teeth)

Motor: mastication

foramen ovale

Abducens Nerves (VI)

  • Function: movement of the lateral rectus eye muscle

  • Classification: Efferent

  • Location: superior orbital fissure

Facial Nerve (VII)

  • Classification: afferent and efferent

  • Note: significant because of its innervation through the parotid salivary gland

  • Clinical Application: Bell’s Palsy

Component

Structures

Motor

muscles of facial expression, lacrimal glands, and submandibular and sublingual glands

Pathway (2):

Lacrimal Gland: facial nerve → pterygopalatine ganglion → lacrimal gland

Salivary Glands: facial nerves → chorda tympani (branch) → submandibular ganglion, submandibular and sublingual salivary glands

Sensory

anterior 2/3 of tongue

Overall Pathway:

enters internal acoustic meatus → facial canal (temporal bone) → stylomastoid foramen (exits)

Vestibulocochlear Nerve (VII)

  • Function: receptors in the inner ear (within the temporal bone) for equilibrium and hearing

  • Classification: afferent

  • Location: internal acoustic meatus

Glossopharyngeal Nerve (IX)

  • Function: signal the optic ganglion to make the parotid gland secrete

  • Classification: afferent and efferent

    • afferent → posterior 1/3 of the tongue, pharyngeal mucosa, and tonsils

    • efferent → stylopharyngeal muscle

  • Location: jugular foramen

  • NOTE: innervates the tongue and pharynx

Vagus Nerve (X)

  • Classification: afferent and efferent

    • afferent → epiglottis

    • efferent → pharynx, larynx, soft palate, smooth muscle, cardiac muscle

  • Location: jugular foramen

  • NOTE: affects body >

Accessory nerve (XI)

  • Two Parts (motor)

    • cranial → larynx, soft palate, and pharynx muscle (swallowing)

    • spinal → sternocleidomastoid and trapezius muscle

  • Location: hypoglossal canal

    • CN IX, X, XI (pharyngeal plexus)

Hypoglossal Nerve (XII)

  • Classification: Efferent

  • Function: innervates tongue

    • hypoglossus

    • styloglossus

    • genioglossus

  • Location: hypoglossal canal