Cranial Nerves

Question 1

What are Cranial Nerves?

Answer 1

• Cranial nerves are LMN’s

that originate from the

brain/brainstem instead of

the spinal cord

• The nuclei of the cranial nerve

(origination point) is

considered a part of the

brainstem and is therefore an

UMN.

• Damage to the nuclei

causes UMN signs and

symptoms

• Brainstem stroke
• Damage to the cranial

nerve itself causes

LMN signs and

symptoms

• Bell’s Palsy
• Guillian Barre
• Cerebrum (2)
• Midbrain (2)
• Pons (4)
• Medulla (4)

Question 2

Pneumonics?

Answer 2

•Oh Oh Oh To Touch

And Feel Very Good

Velvet Ah Heavenly

•Some Say Money

Matters But My

Brother Says Big

Brains Matter Most

Question 3

Pupillary Reflexes

Answer 3

• Direct Pupillary light reflex
• Constriction of the right pupil

when light is shined into the right

eye (Right CN II / Right CN III)

• Consensual Pupillary Reflex-
• Constriction of the left pupil

when light is shined into the right

eye (Right CN II / Left CN III)

*This happens because the optic nerve is literally connected to oculomotor nerve. When the Optic nerve (CN2) senses light, Oculomotor nerve (CN3) constricts the pupil. Eye cannot constrict unless both nerves are working.

*The right and left eyes are connected by the optic nerves. So the optic nerves send signals to both eyes!

e.g. If you shine light in L eye and R eye does not constrict, the damage is in the R oculomotor nerve

Question 4

CN 1

Answer 4

Olfactory Nerve-

• Olfaction (Smell)
• Parkinson’s Disease and

Alzheimer’s Disease early sign

• Test: Sense of Smell
• Close off other nostril
• Use of common, nonirritating

odors

*THIS IS CALLED ANOSMIA

Question 5

CN 2

Answer 5

Optic Nerve-

• Sight/Vision
• Multiple Sclerosis,

Middle/Posterior Cerebral

Artery Stroke

• Test: Central/Peripheral Vision
• Snellen Chart (Central vision)
• Confrontation Test (Peripheral vision)

*DO NOT CHOOSE PRESBYCUSIS- it is a loss of hearing

Question 6

CN 3

Answer 6

Oculomotor Nerve-

• Eye Movement
• Upward, Downward, & Inward
• Multiple sclerosis & Horner’s

Syndrome

• Test
• Follow finger into upward,

downward and inward directions

• Look for strabismus
• Look for ptosis (drooping of eyelid)

Question 7

CN 4

Answer 7

Trochlear Nerve-

• Eye Movement
• Turns eye down when

adducted.

• Multiple sclerosis
• Test
• Ask patient to look down when

eye is adducted

Question 8

CN 5

Answer 8

Trigeminal Nerve-

•Sensory of the face; Muscles of

Mastication

• Trigeminal Neuralgia, ALS
• Test
• Pain and light touch
• Corneal reflex
• Clench teeth & hold against

resistance

• Jaw Jerk reflex

Question 9

CN 6

Answer 9

Abducens

Question 10

CN 7

Answer 10

Facial Nerve-

• Facial expression & taste anterior

two thirds of tongue, CLOSES EYELID

• Bells Palsy, Guillian-Barre, ALS
• Test
• Motor function of the face
• Raise eye brows
• Frown
• Show teeth, smile
• Close eyes tightly
• Puff out both checks
• Apply saline solution and sugar

solution using a cotton swab

Question 11

CN 8

Answer 11

Vestibulocochlear Nerve

Question 12

CN 9

Answer 12

Glossopharyngeal Nerve-

• Taste of back third
• ALS, Medullary stroke

(Wallenberg Syndrome),

Guillain-Barre

• Test
• Apply saline solution and sugar

solution to posterior one third of

tongue

Question 13

CN 10

Answer 13

VAGUS + GLOSSOPHARYNGEAL

•Phonation, Palatal Control, Gag

Reflex

• ALS, Medullary stroke (Wallenberg

Syndrome), Guillain-Barre

• Test
• Swallowing a glass of water
• Say “AH” (Uvula deviates away from

weak side) “U always deviate from something that’s bad”

• Gag reflex

Question 14

CN 11

Answer 14

Spinal Accesory Nerve

Question 15

CN 12

Answer 15

Hypoglossal Nerve-

• Tongue Movements
• ALS
• Test
• Listen to articulation
• Protrude tongue (deviation to weak

side) “Stick your tongue out to the bad guy”

• Move tongue side to side