Cranial Nerves (Week 3)

Olfactory nerve

CN I

Optic nerve

CN II

Oculomotor nerve

CN III

Trochlear nerve

Cranial nerve IV

Trigeminal nerve

Cranial nerve V

Ophthalmic tract

CN V1

Maxillary tract

CN V2

Mandibular tract

CN V3

Abducens nerve

Cranial nerve VI

Facial nerve

Cranial nerve VII

Vestibulocochlear nerve

Cranial nerve VIII

Glossopharyngeal nerve

Cranial nerve IX

Vagus nerve

Cranial nerve X

Accessory nerve

Cranial nerve XI

Hypoglossal nerve

Cranial nerve XII

Peripheral nervous system (PNS)

Part of nervous system composed of spinal and cranial nerves

Cranial nerves

Peripheral nerves attached to the brain

Prosencephalon

Forebrain

Mesencephalon

Mid-brain

Rhombencephalon

Hind-brain

Olfactory, optic

(2) CN from forebrain

Oculomotor, trochlear

(2) CN from midbrain

Special sensory, may

__ __ are cranial nerves for vision, smell, hearing, balance, taste

• They __ (may/will/not) have associated ganglia where cell bodies reside

I, II, VII, VIII, IX, X

The actual CN for vision, smell, hearing, balance, taste

Somatic sensory, will

__ __ are cranial nerves for touch, pain, heat, pressure, and proprioception

• They __ (may/will/not) have associated ganglia where cell bodies reside

V, VII, IX, X

The actual CN for touch, pain, heat, pressure, proprioception

Somatic motor, not

__ __ are cranial nerves for eye and tongue movements, swallowing, speaking, facial expression, chewing

• They __ (may/will/not) have associated ganglia where cell bodies reside

III, IV, V, VI, VII, IX, X, XI, XII

The actual CN for eye and tongue movements, swallowing, speaking, facial expression, chewing

*hint: all but 3

Visceral motor, will

__ __ are cranial nerves for accommodation, lacrimation, salivation, parasympathetic to thoracic and abdominal organs

• They __ (may/will/not) have associated ganglia where cell bodies reside

III, VII, IX, X

The actual CN for accommodation, lacrimation, salivation, parasympathetic to thoracic and abdominal organs

Olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, hypoglossal

Order of Cranial Nerves

On Old Olympus’ Towering Top A Fine Victorian Gentleman Viewed A Hawk

Some Say Marry Money But My Brother Says Big Brains Matter More

Sensory, Motor, Both Role of CNs

• CN I to CN XII pneumonic

Cribriform foramina

Location of CN I

Hyposmia, anosmia

Dysfunction(s) of CN I

Nasal mucosa

CN I SVA from…

Optic canal

Location of CN II

Optic n, bitemporal hemianopia

Dysfunction(s) of CN II

• Prechiasmatic = __

• Chiasmatic = __

Retina

CN II SSA from…

Superior orbital fissure

CN III Location

Levator palpebrae superioris, 3 rectus m., inferior oblique m.

CN III SE goes to…

Pupillary constrictor and ciliary m.

CN III VE goes to…

Oculomotor palsy

Notable ptosis, mydriasis, “down and out”

Superior orbital fissure

CN IV location

Superior orbital fissure

CN VI location

Abducens palsy

Inward deviation of gaze on affected site, patient will maneuver to reduce diplopia

Face, dura mater, teeth, tongue gingiva

Somatic sensory of CN V to…

Muscles of mastication

Somatic motor of CN V to…

Superior orbital fissure

CN V1 location

Foramen rotundum

CN V2 location

Foramen ovale

CN V3 location

CN V3

Division of CN V with most somatic sensory, and some somatic motor function

Ophthalmic, maxillary, mandibular

Branches of Trigeminal nerve

Trigeminal neuralgia

Nerve pain ranging on the branch of CN V affected

Greater petrosal, chorda tympani, facial nerve

3 branches of CN VII

Greater petrosal nerve

Branch of CN VII

• Parasympathetic to lacrimal gland

• Visceral motor

Chorda tympani

Branch of CN VII

• Parasympathetic to salivary gland

• Visceral Motor + Special sensory (taste)

Facial nerve

Branch of CN VII

• Somatic motor to facial expression

• Somatic sensory from auricle

X, X, IX, IX, VII, V3

Corresponding CNs

Internal acoustic meatus, stylomastoid foramen

CN VII location(s)

Temporal, zygomatic, buccal, mandibular, cervical

(5) Sub-branches of facial nerve trunk

Facial nerve palsy (Bell’s Palsy)

Inability to wrinkle brow, drooping eyelid, asymmetrical smile, drooping corner of mouth

Internal auditory meatus

CN VIII location

CN IX, X, XI

CNs within jugular foramen

Foramen ovale

Tympanic branch of CN IX location

Pharyngeal constrictor and laryngeal m.

CN X somatic motor to…

Heart, most of abdominal organs

CN X visceral motor to…

External auditory meatus

CN X somatic sensory from…

Epiglottis

CN X special sensory from…

Trachea, bronchial tree, viscera of thorax/abdomen

CN X visceral sensory from…

Foramen magnum and jugular foramen

CN XI location(s)

C1-C5

Spinal roots of CN XI - spinal levels

Intrinsic muscles of tongue

Longitudinal, vertical, and transverse muscle fibers of tongue // for shape of tongue

Extrinsic muscles of tongue

Hyoglossus, genioglossus, styloglossus, palatoglossal m. // for moving tongue

Hypoglossal palsy

Paralysis of genioglossus unilaterally, with tongue protruding toward injured site