Cranial Nerves

II Optic

CN IX: Glossopharyngeal

CN V: Trigeminal

CN VI: Abducens

CN VIII: Vestibulocochlear

CN VII: Facial

CN IV Throclear

touch - pain - temperature

CN XI: Accesory

CN X: Vagus

III Oculomotor

I Olfactory

Anosmia/Disosmia

Sensory

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only CN without thalamic relay to cortex

Cribiform plate - anterior cranial fossa

Anopsia

Loss of light reflex with III

Only affected by MS - olygodendrocytes

CN II axons linked in the pretectal area - Parasympathetic CN III fibers - Reflexes are bilateral

adduction - MR

levator palpebrae superioris

sphincter pupillae contricts pupil

cilliary muscle

diplopia/external strabismus/loss of parallel gaze ⚠

ptosis

loss of light reflex ⚠

miosis

loss of near response

Depression and abduction - SO

intortion - SO

weakness looking down from adduction

Diplopia while reading, going downstairs ⚠

TEST: ask to look down from an adducted position

Extorted eye - Head tilts away from lesioned eye ⚠

Lateral rectus - Abduction

Diplopia, internal strabismus

loss of parallel gaze "pseudoptosis"

V3 Mandibular

V2 Maxillary

V1 Ophtalmic

Skin of the forehead/scalp/cornea/dorsum of the nose

Palate, nasal cavity, maxillary face, teeth

Blink reflex afferent ⚠ lesion

anterior 2/3 of tongue, mandibular face, teeth

weakness in chewing

mastication muscles

temporalis, masseter, medial and lateral pterygoids

mandible elevation ⚠ jaw deviation toward weak side

anterior belly of digastric, mylohyoid, tensor timpani and palati

trigeminal neuralgia intractable pain in V2/V3 ⚠

Facial expression/Stapedius

Salivation

Skin behind ear ⚠ pain

Taste in anterior 2/3 of tongue/palate ⚠ ageusia

tears - lacrimal gland ⚠eye dry and red

⚠ corner of mouth droops, cannot close eye or wrinkle forehead, loss of blink reflex

hyperacusis - Bell palsy in facial canal

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stylohyoid, posterior belly of digastric

Sensory

Hearing ⚠ Sensorineural hearing loss

Angular acceleration (Head turning)

Linear acceleration

dizzyness, vomiting, ..

Vestibular evoked nystagmus

Motor

Stylopharyngeus

Parasympathetic

Parotid gland - Salivation

Sensation

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of post 1/3 of tongue

Carotid sinus/body

oropharynx

gag reflex - X: afferent and efferent

Parasympathetic

Sensory

Motor

all muscles of the palate excepti: IX and V ⚠ palate droop, nasal speech, dysphagia, regurgitation, uvula points away from affected side

larynx - phonates

Larynx + Laryngopharynx

GI tract

GI tract, foregut, midgut

Hoarseness/fixed vocal corg

Loss of gag reflex

loss of cough reflex

Head rotation to opposite side SCM ⚠weakness turning chin to opposite side

Elevates and rotates scapula

Shoulder droop ⚠

CN XII: Hypoglossal

Tongue movement genioglossus, stylo, hyo, intrinsic tongue muscles

tongue deviation toward same affected side ⚠

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