Cranial nerves

Question 1

I (Olfactory) Smell Cribriform plate

Question 2

II (Optic) Sight

Answer 2

Optic canal

Question 3

Eye movement (MR, IO, SR, IR)
Pupil constriction
Accomodation
Eyelid opening

Answer 3

CN III oculomotor

Question 4

Palsy results in
ptosis
‘down and out’ eye
dilated, fixed pupil

Answer 4

CN III oculomotor

Question 5

CN III oculomotor exit pathway/foramen

Answer 5

Superior orbital fissure

Question 6

Responsible for Eye movement (SO)
Palsy results in defective downward gaze → vertical diplopia
Exits through Superior orbital fissure (SOF)

Answer 6

CN IV Trochlear

Question 7

Actions:
Facial sensation
Mastication

Lesions may cause:
trigeminal neuralgia
loss of corneal reflex (afferent)
loss of facial sensation
paralysis of mastication muscles
deviation of jaw to weak side

Answer 7

CN V Trigeminal

Question 8

Exit pathway/foramen of trigeminal nerve

Answer 8

V1: Superior orbital fissure (SOF)
V2: Foramen rotundum,
V3: Foramen ovale

Question 9

Responsible for:
Eye movement (LR)
Palsy results in defective abduction → horizontal diplopia
Exits pathway Superior Orbital Fissure

Answer 9

CN VI abducens

Question 10

Controls:
Facial movement
Taste (anterior 2/3rds of tongue)
Lacrimation
Salivation

Answer 10

CN VII Facial nerve

Question 11

Lesions may result in:
flaccid paralysis of upper + lower face
loss of corneal reflex (efferent)
loss of taste
hyperacusis

Answer 11

CN VII Facial nerve

Question 12

Exit pathway of CN VII and VIII

Answer 12

Internal auditory meatus

Question 13

Responsible for Hearing, + balance

Lesions can cause:
Hearing loss
Vertigo, nystagmus
Acoustic neuromas are Schwann cell tumours of the cochlear nerve

Answer 13

CN VIII vestibulocochlear

Question 14

Responsible for:
Taste (posterior 1/3rd of tongue)
Salivation
Swallowing
Mediates input from carotid body & sinus

Lesions may result in;
hypersensitive carotid sinus reflex
loss of gag reflex (afferent)

Answer 14

CN IX Glossopharyngeal

Question 15

Responsible for:
Phonation
Swallowing
Innervates viscera

Lesions may result in;
uvula deviates away from site of lesion
loss of gag reflex (efferent)

Answer 15

CN X Vagus

Question 16

Exit pathway of CN IX, X and XI

Answer 16

Jugular foramen

Question 17

Responsible for:
Head and shoulder movement

Lesions may result in;
weakness turning head to contralateral side

Answer 17

CN XI Spinal Accessory

Question 18

Responsible for:
Tongue movement

Lesions may cause:
Tongue deviates towards side of lesion

Answer 18

CN XII Hypoglossal

Question 19

Exit pathway/foramen of CN XII

Answer 19

Hypoglossal canal

Question 20

Where in the brainstem are the CN nuclei located?

Answer 20

Midbrain CN III-IV
Pons CNV-VIII
Medulla CN IX-XII

Question 21

Corneal Reflex

Answer 21

Afferent limb: Ophthalmic nerve (V1)
Efferent Limb: Facial nerve (VII)

Question 22

Jaw jerk reflex

Answer 22

Afferent and Efferent: Mandibular nerve (V3)

Question 23

Gag reflex

Answer 23

Afferent: Glossopharyngeal nerve (IX)
Efferent: Vagal nerve (X)

Question 24

Carotid sinus reflex

Answer 24

Afferent: Glossopharyngeal nerve (IX)
Efferent: Vagal nerve (X)

Question 25

Pupillary Light Reflex

Answer 25

Afferent: Optic nerve (II)
Efferent: Oculomotor nerve (III)

Question 26

Lacrimation Reflex

Answer 26

Afferent: Ophthalmic nerve (V1)
Efferent: Facial nerve (VII)