Cranial Nerves

Question 1

Describe the best visual pathway

Answer 1

• Retina to optic nerve to optic chiasm to optic tract to lateral geniculate nucleus to optic radiation to visual cortex

Question 2

What do intaocular movements refer to

Answer 2

• concern the contraction and dilation of the pupil and movements controlling the lens

Question 3

What are extra ocular eye movements

Answer 3

• relate to the movements of the globe itself

Question 4

what allows the eye to move

• upward
• lateral
• inferior
• medial
• lateral rotation and medial
• medial rotation and lateral

Answer 4

• upward = superior rectus
• lateral = lateral rectus
• inferior = inferior rectus
• medial = medial rectus
• lateral rotation and medial = inferior oblique
• medial rotation and lateral = superior oblique

Question 5

What nerve innervates the superior oblique

Answer 5

CN IV

Question 6

What nerve innervates the lateral rectus

Answer 6

CN VI

Question 7

What nerve innervates the superior rectus, inferior rectus, medial rectus, inferior oblique

Answer 7

CN III

Question 8

What control facial movement

Answer 8

• CNV - Trigeminal

- CNVII - Facial

Question 9

what controls the superior half of the face

Answer 9

• both the left and right primary motor cortex

Question 10

What controls the inferior half of the face

Answer 10

• derives conscious control from only the contralateral primary motor cortex

Question 11

Where does the motor component of the facial nerve arise from

Answer 11

• ponto-medullary junction

Question 12

where is the facial nucleus located

Answer 12

• The facial motor nucleus is located in the caudal portion of the ventrolateral pontine tegmentum.
• Axons travel dorsally then loop around the abducens nucleus, before moving ventrally to exit the ventral pons medial to the spinal trigeminal nucleus

Question 13

where does the facial nerve exit the skull

Answer 13

• the facial nerve exits the skull via the internal auditory meatus and runs through the temporal bone which the motor component then exits through the stylomastoid foramen entering the parotid gland

Question 14

What are the motor branches of the parotid nerve

Answer 14

• temporal
• zygomatic
• buccal
• mandibular
• cervical

Question 15

What are the main muscles of mastication

Answer 15

• Masseter
• temporalis
• pterygoids

Question 16

What is the key reason for eye movements being paired each side

Answer 16

• to enable binocular vision and prevent double vision

Question 17

if there is ipsilateral unilateral eye loss

Answer 17

• optic neuritis
• glaucoma
• trauma
• optic atrophy

Question 18

What can cause a bitemporal hemianopia

Answer 18

• pituitary tumour - worse in upper fields

- Craniopharyngioma - worse in lower fields

Question 19

What causes homonymous field defects

Answer 19

• Stroke

- Tumours

Question 20

What is nystagmus

Answer 20

• jerky eye movements when moving gaze horizontally

Question 21

What happens in 3rd nerve palsy

Answer 21

• downward and outward pointing eye

- ptosis - dropping upper eyelid

Question 22

What happens in a 4th nerve palsy

Answer 22

• upwards and outwards turning of the eye

Question 23

What happens in a 6th nerve palsy

Answer 23

• abduction of eye at rest with failure of lateral gaze

Question 24

How many muscles are there in the face

Answer 24

43 muscles

Question 25

what muscles do the 5 branches of the facial nerve control

• temporal
• zygomatic
• buccal
• marginal mandibular
• cervical

Answer 25

• temporal = frontalis, orbicularis oculi
• zygomatic - orbiculares oculi
• buccal - buccinator, risorius, nasals, orbicularis fris, zygomaticus muscle
• marginal mandibular - mentalis
• cervical - platysma

Question 26

describe the difference between an upper and lower motor neurone lesion of the face

Answer 26

• LMN - result in paralysis of all facial movements

- UMN - result in only lower facial paralysis

Question 27

What can cause an UMN of the face

Answer 27

Stroke

Question 28

What can cause a LMN issue of the face

Answer 28

• bells palsy

- parotid lesion