Cranial Nerve Screens

Question 1

What is cranial nerve I?

Answer 1

Olfactory

Question 2

How do you test the Olfactory nerve?

Answer 2

Have them smell something and tell you what it is. For example, an alcohol pad.

Question 3

Is Cranial Nerve I sensory or motor?

Answer 3

Purely sensory. It’s function is smell.

Question 4

What are possible abnormal findings in CN 1?

Answer 4

Anosmia: an inability to detect smells

Seen with frontal lobe lesions

Question 5

Optic Nerve

Answer 5

Cranial Nerve II
Function: vision
Purely sensory

Question 6

How do you test CN 2?

Answer 6

Test visual acuity.
Central: Snellen eye chart; test each eye separately at a distance of 20 feet
Peripheral vision (visual fields): by confrontation - have patient sum fingers you are holding up

Question 7

What are possible abnormal findings for CN 2?

Answer 7

Blindness, myopia (nearsightedness), presbyopia (farsightedness)

Field defects: homonymous hemianopsia

Question 8

Cranial Nerve 3

Answer 8

Oculomotor
Function: Pupillary reflexes
Purely motor

Question 9

How do you test Oculomotor?

Answer 9

Use the H test.
Test pupillary reactions by shining light in eye
If abnormal, test near reaction.
Examine pupillary size/shape

Question 10

What are possible abnormal findings for the oculomotor nerve?

Answer 10

Absence of pupillary constriction
Anisocoria (unequal pupils)
Horner’s syndrome, CN 3 paralysis

Question 11

Trochlear Nerve

Answer 11

CN 4
Function: extraocular movements. Pupillary constriction and eye movements.
Purely motor

Question 12

How do you test CN 4?

Answer 12

H test

Question 13

What are possible abnormal findings for CN 4?

Answer 13

Strabismus (eye deviates from normal conjugate position)
Impaired eye movements
Double vision

Question 14

Cranial Nerve 5

Answer 14

Trigeminal nerve
Function: sensory - face
sensory - cornea
motor - muscles of mastication

Question 15

How do you test CN 5?

Answer 15

Palpate the temporal and masseter muscles while they clench

Question 16

What are possible abnormal findings for the trigeminal nerve?

Answer 16

Loss of facial sensations or weakness and wasting of muscles

When opened, deviation of jaw to ipsilateral side

Question 17

Abducens Nerve

Answer 17

Cranial Nerve 6
Function: Lateral rectus: turns eye out
Purely motor

Question 18

How do you test CN 6?

Answer 18

H test (lateral tracking)

Question 19

What are possible abnormal findings for the abducens?

Answer 19

Esotropia (eye pulled inward)

Eye cannot look out

Question 20

Cranial Nerve 7

Answer 20

Facial nerve
Function: facial expression.
Taste to anterior two thirds of tongue
Mixed motor and sensory

Question 21

How do you test the facial nerve?

Answer 21

Raise eyebrows, puff out cheeks, smile

Question 22

What are possible abnormal findings in the facial nerve?

Answer 22

Paralysis:

inability to close eye, drooping corner of mouth, and difficulty with speech articulation

Question 23

Vestibulocochlear nerve

Answer 23

Cranial nerve 8
Function: vestibular function and cochlear function. Equilibrium.
Purely sensory

Question 24

How do you test CN 8?

Answer 24

Rub fingers next to both ears or whisper

Weber’s test = vibration on the forehead

Question 25

What are possible abnormal findings for CN 8?

Answer 25

Vertigo, dysequilibrium, nystagmus Deafness, tinnitus Conductive loss

Question 26

Cranial Nerve 9

Answer 26

Glossopharyngeal Function: Sensory to posterior one third of tongue, pharynx, middle ear Mixed motor and sensory

Question 27

How do you test CN 9?

Answer 27

Gag reflex | Not usually tested

Question 28

Vagus nerve

Answer 28

Cranial nerve 10 Function: vocal sounds, swallowing, pharynx control Mixed motor and sensory

Question 29

How do you test the vagus nerve?

Answer 29

Have the patient say "ah" and check for uvula deviation

Question 30

What are possible abnormal finding for CN 10?

Answer 30

Paralysis: palate fails to elevate | Asymmetrical elevation

Question 31

Cranial Nerve 11

Answer 31

Spinal accessory nerve Function: motor - trapezius muscle, sternocleidomastoid Purely motor

Question 32

How do you test CN 11?

Answer 32

Test the same way as C4 myotome

Question 33

What are possible abnormal finding for CN 11?

Answer 33

LMN: atrophy, ipsilateral weakness, inability to shrug ipsilateral shoulder UMN: weakness of ipsilateral sternocleidomastoid and contralateral trapezius

Question 34

Hypoglossal nerve

Answer 34

Cranial Nerve 12 Function: Tongue movements Purely motor

Question 35

How do you test CN 12?

Answer 35

Patient pushes tongue into cheek and then examiner resists OR pt protrudes tongue and watch for deviation

Question 36

What are possible abnormal findings for CN 12?

Answer 36

Dysarthria, impaired movements, deviation to weak side