CN Physical Exam

Question 1

How do you test CN I?

Answer 1

test for odor identification (coffee, cinnamon)

Question 2

How do you test CN II function?

Answer 2

• test for visual acuity
• test for visual fields

Question 3

Which CNs are tested together?

Answer 3

CN III, IV, VI

Question 4

How do you test for function of CN III, IV, VI?

Answer 4

• inspect eyelids for drooping (levator palpabrae superioris innervated w sympathetics and CN III)
• inspect pupils for size and equality (CN III)
• test consensual response and accommodation
• test extraocular eye movements (CN IV and VI)

Question 5

In an abnormal eye that has oculomotor nerve palsy, what would you expect?

Answer 5

• ptosis (inactivation of levator palpebrae)
• mydriasis (decreased tone of constrictor pupillae mm)
• down and out (unopposed left superior oblique and lateral rectus mm)

Question 6

What happens in cranial nerve IV palsy?

Answer 6

• Downward and outward movement is affected
• slight head tilt to normal side; superior and lateral drift of eye
• increased upward and inward leads to diplopia

Question 7

What happens in CN VI palsy?

Answer 7

• affected eye adducts appropriately but fails to abduct resulting in diplopia
• will have cavernous sinus issues

Question 8

• Describe CN III palsy
• Describe CN IV palsy
• Describe CN VI palsy

Answer 8

• lateral deviation; downward deviation, ptosis
• upward deviation
• medial deviation

Question 9

How do you test for CN V function?

Answer 9

• inspect face for atrophy and tremor
• palpate jaw for tone and strength
• test for pain and sensation
• test for corneal reflex (ophthalmic)

Question 10

In more description, how can you test motor examination of trigeminal n?

Answer 10

• muscle power of mastication mm (masseter and temporalis)
• inability to raise, depress, protrude, and retract and deviate the mandible
• jaw deflected toward same side

Question 11

Corneal reflex is in by (…) and out by (…)

Answer 11

• in: CN V
• out: CN VII

Question 12

How do you test CN VII function?

Answer 12

• facial expressions
• test anterior 2/3 of tongue for salty and sweet

Question 13

How do you test for CN VIII function?

Answer 13

• test hearing and equilibrium
• bone and air conducting using weber and rinne tuning forks

Question 14

Describe rombergs test

Answer 14

• have person close eyes and gently push to test balance
• positive if patient falls without correction

Question 15

How do you test for CN IX function?

Answer 15

• test posterior 1/3 of tongue for sour and bitter taste
• test gag reflex and swallow
• CN IX is sensory component of the gag reflex

Question 16

How do you test for CN X function?

Answer 16

• say ahhh
• inspect palate and uvula for symmetry, inspect for swallow difficulty, evaluate guttural speech sounds (laryngeal muscles)

Question 17

In a CN IX lesion, the uvula does what?

Answer 17

deviates away from lesion

Question 18

How do you test for CN XI function?

Answer 18

• trapezius: shrug shoulders up against resistance
• sternocleidomastoid: turn head against resistance
• SCM actions: ipsilateral head tilt and contralateral rotation

Question 19

How do you test for CN XII function?

Answer 19

• inspect tongue for symmetry/tremors/atrophy
• test tongue movement
• test tongue strength
• evaluate lingual speech sounds

Question 20

In a CN XII lesion, how does the tongue deviate?

Answer 20

tongue deviates toward lesion