Cranial Nerves

Question 1

Sensory only CNs

Answer 1

1, 2, 8

Question 2

Morot only CNs

Answer 2

3, 4, 6, 11, 12

Question 3

Mixed modalities CNs

Answer 3

5, 7, 9, 10

Question 4

Only CN to be affected by MS

Answer 4

2

Question 5

Lesion to CN III

Answer 5

• Diplopia, loss of parallel gaze, external strabismus, ptosis
• Dilated pupil, loss of light reflex with CN II, loss of near response

Question 6

What CN constricts pupil

Answer 6

CN III - sphincter pupillae

Question 7

What CN is responsible for accommodation

Answer 7

CN III –> ciliary muscle

Question 8

What CN raises eyelid?

Answer 8

CN III –> levator palpebrae superioris

Question 9

Lesion to CN IV

Answer 9

• Trouble going down stairs

- Head tilts away from lesioned side

Question 10

Superior oblique

Answer 10

CN IV –> depresses and abducts (makes eye look down and out)

Question 11

Opthalmic division of V (V1)

Answer 11

General sensation (touch, pain, temp) of forehead/scalp/cornea

Question 12

Lesion to V1

Answer 12

• Loss of sensation on forehead/scalp

- Loss of corneal reflex with VII

Question 13

Maxillary division of V (V2)`

Answer 13

General sensation of palate, nasal cavity, maxillary face, maxillary teeth

Question 14

Lesion to V2

Answer 14

Loss of sensation in skin over maxilla and maxillary teeth

Question 15

Mandibular division of V (V3)

Answer 15

• General sensation of anterior 2/3 of tongue, mandibular face and teeth
• Motor to muscles of mastication

Question 16

Lesion to V3

Answer 16

• Loss of general sensation over mandible and mandibular teeth
• Weakness in chewing
• Law deviates towards weak side

Question 17

Trigeminal neuralgia

Answer 17

Intractible pain in V2 or V3 territory

Question 18

CN VI

Answer 18

Lateral rectus (abducts eyeball)

Question 19

Lesion to CN VI

Answer 19

Diplopia, internal strabismus, loss of parallel gaze, “pseudoptosis”

Question 20

CN VII

Answer 20

• Muscles of facial expression
• Salivation (submandibular, sublingual)
• Stapedius, posterior belly of digastric stylohyoid
• Taste on anterior 2/3 of tongue
• Tears (lacrimal gland)

Question 21

CN VII lesion

Answer 21

Corners of mouth droop, can’t change facial expression, hyperaccusis
Bell’s palsy - lesion of nerve in facial canal
- Loss/changes in taste
- Dry/red eyes

Question 22

CN VIII

Answer 22

Hearing
Angular acceleration (head turning)
Linear acceleration (gravity)

Question 23

Lesion to CN VIII

Answer 23

Sensorineural hearing loss

Loss of balance, nystagmus

Question 24

CN IX

Answer 24

• Sense of pharynx, carotid sinus/body
• Salivation (parotid gland)
• Taste and sensation of posterior 1/3 of tongue
• Motor to one muscle: stylopharyngeus

Question 25

Lesion to CN IX

Answer 25

Loss of gag reflex with CN X

Question 26

CN X

Answer 26

• To muscles of palate and pharynx for swallowing except for tensor palati (V) and stylopharyngeus (IX)
• To all muscles of larynx (phonates)
• Sensory of larynx and laryngopharynx
• Sensory of GI tract
• To GI tract smooth muscle and glands in foregut and midgut

Question 27

Lesion to CN X

Answer 27

• Nasal speech/regurgitation
• Dysphagia, palate droop
• Uvula pointing away from affected side
• Hoarseness
• Loss of gag reflex with IX
• Loss of cough reflex

Question 28

CN XI

Answer 28

• Head rotation to opposite side (SCM)

- Elevates and rotates scapula (trapezius)

Question 29

Lesion to CN XI

Answer 29

• Weakness turning head to opposite side

- Shoulder droop

Question 30

CN XII

Answer 30

• Tongue movement, except palatoglossus (X)

Question 31

Lesion to CN XII

Answer 31

Tongue pointing to same (affected) side on protrusion