Cranial Nerve Examination

Question 2

What is the purpose of a cranial nerve exam?

Answer 2

To assess the function of each cranial nerve through observation and specific tests.

Question 3

How many cranial nerves are there?

Answer 3

12 pairs.

Question 4

Which cranial nerves have both sensory and motor functions?

Answer 4

V (Trigeminal), VII (Facial), IX (Glossopharyngeal), X (Vagus).

Question 5

Which cranial nerves have parasympathetic functions?

Answer 5

CN III, VII, IX, X.

Question 6

What is the function of CN I (Olfactory)?

Answer 6

Sense of smell.

Question 7

How do you test CN I?

Answer 7

Ask about changes in smell; have patient smell a substance like coffee with one nostril closed.

Question 8

What is anosmia?

Answer 8

Inability to smell.

Question 9

What can interfere with CN I testing?

Answer 9

Mucus, smoking.

Question 10

What is the function of CN II (Optic)?

Answer 10

Vision.

Question 11

How do you test CN II visual acuity?

Answer 11

Use a Snellen chart.

Question 12

What is bitemporal hemianopsia?

Answer 12

Loss of vision in the outer half of both eyes (optic chiasm lesion).

Question 13

What is homonymous hemianopsia?

Answer 13

Loss of the same visual field in both eyes (optic tract lesion).

Question 14

What is homonymous hemianopsia with macular sparing?

Answer 14

Vision loss sparing the macula, usually from geniculocalcarine tract lesion.

Question 15

How do you test CN II visual fields?

Answer 15

Patient covers one eye and follows examiner’s finger moving into peripheral vision.

Question 16

What is the consensual light reflex?

Answer 16

Pupil constriction in the opposite eye when light is shined into one eye.

Question 17

What is the pupillary reflex?

Answer 17

Pupil constriction in the eye that receives the light.

Question 18

What is the function of CN III (Oculomotor)?

Answer 18

Eye movement (up, down, in), pupil constriction, raises eyelid.

Question 19

What are signs of CN III dysfunction?

Answer 19

Ptosis, diplopia, loss of light/accommodation reflexes.

Question 20

How do you test CN III eye position?

Answer 20

Observe if both eyes look in the same direction.

Question 21

How do you test CN III smooth pursuit?

Answer 21

Have the patient follow your finger up, down, and inward.

Question 22

What happens with a CN III lesion during convergence testing?

Answer 22

One eye may not move medially.

Question 23

How do you test accommodation?

Answer 23

Have patient focus on a far object, then near object (e.g., examiner’s nose).

Question 24

What is the function of CN IV (Trochlear)?

Answer 24

Moves eye downward and inward.

Question 25

What are signs of CN IV dysfunction?

Answer 25

Double vision, difficulty reading, especially on stairs.

Question 26

How do you test CN IV?

Answer 26

Move finger inward and downward while patient follows with eyes.

Question 27

What is the function of CN V (Trigeminal)?

Answer 27

Facial sensation, chewing.

Question 28

What are the three branches of CN V?

Answer 28

Ophthalmic, maxillary, mandibular.

Question 29

What is trigeminal neuralgia?

Answer 29

Intense facial pain, often like an electric shock.

Question 30

How do you test CN V sensory?

Answer 30

Use light touch and pinprick on forehead, cheek, chin.

Question 31

How do you test CN V motor?

Answer 31

Tap chin with reflex hammer; observe masseter contraction.

Question 32

What is the corneal reflex?

Answer 32

Eye blinks when cornea is touched.

Question 33

Which cranial nerves control the corneal reflex?

Answer 33

Afferent: CN V, Efferent: CN VII.

Question 34

How do you test jaw strength?

Answer 34

Manual muscle test and palpation of masseter during clenching.

Question 35

What is the function of CN VI (Abducens)?

Answer 35

Abducts the eye (moves it laterally).

Question 36

How do you test CN VI?

Answer 36

Observe eye position and have patient follow your finger laterally.

Question 37

What are signs of CN VI dysfunction?

Answer 37

One eye looks inward; patient has double vision.

Question 38

What is the function of CN VII (Facial)?

Answer 38

Facial expression, taste, lacrimation, salivation.

Question 39

How do you test CN VII motor function?

Answer 39

Ask patient to smile, puff cheeks, close eyes, wrinkle forehead.

Question 40

What are signs of CN VII dysfunction?

Answer 40

Paralysis or paresis of ipsilateral facial muscles.

Question 41

What is the function of CN VIII (Vestibulocochlear)?

Answer 41

Balance and hearing.

Question 42

What is conductive deafness?

Answer 42

Hearing loss from outer/middle ear issues (e.g., wax, inflammation).

Question 43

What is sensorineural deafness?

Answer 43

Hearing loss from inner ear or nerve damage (e.g., ototoxic drugs).

Question 44

What is tinnitus?

Answer 44

Ringing or buzzing in the ears.

Question 45

How do you test CN VIII?

Answer 45

Rub fingers near each ear and compare response.

Question 46

What is the Rinne test?

Answer 46

Vibrating tuning fork on mastoid then next to ear; air conduction should be longer.

Question 47

What is an abnormal Rinne test?

Answer 47

Bone conduction equal or longer than air conduction.

Question 48

What is the Weber test?

Answer 48

Tuning fork on top of head; sound should be midline.

Question 49

What is an abnormal Weber test?

Answer 49

Sound is louder in one ear, suggesting hearing imbalance.

Question 50

What is the function of CN IX (Glossopharyngeal)?

Answer 50

Taste, salivation, swallowing, gag reflex.

Question 51

How do you test CN IX?

Answer 51

Touch soft palate for gag reflex or have patient say “ah” and observe palate movement.

Question 52

What is an abnormal gag reflex?

Answer 52

No gag or asymmetric palate elevation.

Question 53

What is the function of CN X (Vagus)?

Answer 53

Regulates viscera, speech, swallowing.

Question 54

What are signs of CN X dysfunction?

Answer 54

Hoarseness, swallowing difficulty, poor digestion.

Question 55

How do you test CN X?

Answer 55

Same as CN IX—check swallowing and palate elevation.

Question 56

What is the function of CN XI (Spinal Accessory)?

Answer 56

Elevates shoulders and turns head (SCM, trapezius).

Question 57

How do you test CN XI?

Answer 57

MMT of sternocleidomastoid and trapezius.

Question 58

What are signs of CN XI dysfunction?

Answer 58

Weakness or paralysis of SCM and/or trapezius.

Question 59

What is the function of CN XII (Hypoglossal)?

Answer 59

Tongue movement.

Question 60

How do you test CN XII?

Answer 60

Have patient stick out tongue and push against cheek.

Question 61

What are signs of CN XII dysfunction?

Answer 61

Tongue deviation to lesion side; atrophy.

Question 62

What cranial nerves are involved in the pupillary reflex?

Answer 62

Afferent: CN II, Efferent: CN III.

Question 63

What cranial nerves are involved in the corneal reflex?

Answer 63

Afferent: CN V, Efferent: CN VII.

Question 64

What cranial nerves are involved in the masseter reflex?

Answer 64

CN V afferent and efferent.

Question 65

What cranial nerves are involved in the gag reflex?

Answer 65

Afferent: CN IX, Efferent: CN X.

Question 66

What cranial nerves are involved in the swallowing reflex?

Answer 66

Afferent: CN IX, Efferent: CN X.

Question 67

What is convergence?

Answer 67

Both eyes adducting as they focus on a near object.

Question 68

What is the normal distance for convergence?

Answer 68

6–10 cm from the nose.

Question 69

What are the three components of accommodation?

Answer 69

Lens focusing, pupillary constriction, eye adduction.

Question 70

What muscle elevates the upper eyelid?

Answer 70

Levator palpebrae superioris (CN III).

Question 71

What muscle moves the eye laterally?

Answer 71

Lateral rectus (CN VI).

Question 72

What muscle moves the eye downward and inward?

Answer 72

Superior oblique (CN IV).

Question 73

What causes diplopia?

Answer 73

Misalignment of the eyes due to CN III, IV, or VI dysfunction.

Question 74

What cranial nerve is most commonly affected in increased intracranial pressure?

Answer 74

CN VI.

Question 75

Which cranial nerves exit from the medulla?

Answer 75

CN IX, X, XI, XII.

Question 76

Which cranial nerve is the only one to exit the brain dorsally?

Answer 76

CN IV.

Question 77

What nerve controls the anterior 2/3 of tongue taste?

Answer 77

CN VII (Facial).

Question 78

What nerve controls the posterior 1/3 of tongue taste?

Answer 78

CN IX (Glossopharyngeal).

Question 79

Which cranial nerve controls hearing?

Answer 79

CN VIII (Vestibulocochlear).

Question 80

Which cranial nerve has the longest course in the body?

Answer 80

CN X (Vagus).

Question 81

What is a sign of a lower motor neuron lesion of CN VII?

Answer 81

Facial weakness affecting both upper and lower face.

Question 82

What is a sign of an upper motor neuron lesion of CN VII?

Answer 82

Lower face weakness only.

Question 83

What cranial nerve controls sternocleidomastoid and trapezius?

Answer 83

CN XI (Accessory).

Question 84

What does deviation of the tongue indicate?

Answer 84

Lesion on the same side (CN XII).

Question 85

What are the lab skills related to cranial nerve exam?

Answer 85

Performing a complete CN exam with a partner.

Question 86

Why is a cranial nerve exam clinically important?

Answer 86

Helps localize brainstem or peripheral nerve lesions.