Cranial Nerves and Cranial Nerve Testing

Question 1

CN I

Answer 1

Olfactory nerve

Special Sensory - Smell

Question 2

CN II

Answer 2

Optic nerve

Special Sensory - Sight

Question 3

CN III

Answer 3

Oculomotor nerve (entirely motor)

Somatic Motor - supplies innervation to 4 of the 6 extraocular muscles (superior, medial, inferior rectus muscles, inferior oblique) and the levator palpebrae superioris which raises the eyelids

Visceral Motor - innervates smooth muscle of the eyeball, pupillary constrictor (constricts pupil) and ciliary muscles (change lens shape)

Question 4

CN IV

Answer 4

Trochlear nerve

Somatic Motor - innervates superior oblique muscle of eyeball (turns eye downward and laterally)

Question 5

CN V

Answer 5

Trigeminal nerve (opthalamic division, maxillary division, mandibular division)

Question 6

CN VI

Answer 6

Abducens nerve

Question 7

CN VII

Answer 7

Facial nerve

Question 8

CN VIII

Answer 8

Vestibulochochlear nerve

Question 9

CN IX

Answer 9

Glossopharyngeal nerve

Question 10

CN X

Answer 10

Vagus nerve

Question 11

CN XI

Answer 11

Accessory nerve

Question 12

CN XII

Answer 12

Hypoglossal nerve

Question 13

CN I Testing

Answer 13

Patient is seated with eyes closed or blindfolded. Therapist places an item with a familiar odor under the patient’s nostril and the patient is asked to identify the odor.

Positive test may be indicated by an inability to identify familiar odors (Olfactory nerve).

Question 14

CN III Testing

Answer 14

Patient is seated and asked to follow an object such as a pen with their eyes as it is moved vertically, horizontally, and diagonally. Make sure the patient does not rotate their head during the testing and should inspect the patent’s eyes for symmetry and ptosis.

Positive test is indicated by an identified tracking deficit, asymmetry or ptosis .

Question 15

CN II Testing

Answer 15

Patient is standing at a selected distance from a chart or diagram. Therapist asks the patient to identify objects or read selected items from the chart of diagram.

Positive test may be indicated by an inability to identify objects at a reasonable distance (Optic nerve).

Question 16

CN IV Testing

Answer 16

Patient is seated and asked to follow an object like a pen with their eyes as it is moved in an inferior and lateral direction. Therapist should make sure the patient does not move their head downward.

Positive test is indicated by an inability to depress the eyes and/or complaints of diplopia

Question 17

CN V Testing

Answer 17

Patient is seated and asked to close their eyes. Therapist uses a piece of cotton and safety pin to alternately touch patient’s face. Patient is asked to classify each contact with “sharp” or “dull”.

Positive test for sensory component may be identified as inability to differentiate between sharp and dull.

Motor component is tested by asking patient to perform mandibular protrusion, retrusion, and lateral deviation.

Positive test for motor component may be indicated by impaired ability to mov the mandible through listed motions.

Question 18

CN VI Testing

Answer 18

Patient is sitting, therapist asks patient to abduct their eyes without rotating their head,

Positive test if unable to abduct eyes.

Question 19

CN VII Testing

Answer 19

Patient is seated and asked to distinguish between sweet and salty substances placed on the anterior portion of their tongue.

Motor component is tested by testing strength of muscles involved in facial expression through asking patient to perform specific facial expressions.

Positive tests may be indicated if patient is unable to accurately identify sweet and salty substances or mimic selected facial expressions due to muscle impairment.

Question 20

CN VIII Testing

Answer 20

Patient seated in quiet environment, therapist is positioned behind the patient

Question 21

CN IX Testing

Question 22

CN X Testing

Answer 22

Patient is seated, therapist touches the pharynx with a tongue depressor.

Positive test may be indicated by a lack of gagging or an inability to feel the tongue depressor touch the back of the throat.

Question 23

CN XI Testing

Answer 23

Patient is seated with arms at side. Therapist asks patient to shrug their shoulders and maintain the position while the therapist applies resistance though the shoulder in the direction of shoulder depression.

Positive test may be indicated by an inability to maintain the test position against resistance.

Question 24

CN XII Testing

Answer 24

Patient is seated and therapist asks the patient to protrude the tongue.

Positive test may be indicated by an inability to fully protrude the tongue or the tongue deviating to one side during protrusion.