2. The facial nerve

Question 1

Which cranial nerve is facial nerve?

Answer 1

CN 7

Question 2

What fibers does facial nerve have?

Answer 2

Mainly motor, but also sensory (parasymp and taste)

Question 3

Where is facial nerve motor nucleus located?

Answer 3

In pons

Question 4

What is the function of motor nucleus of facial nerve?

Answer 4

• Facial expression
• Posterior belly of digastric
• Stylohyoid

Question 5

Pathway of facial nerve

Answer 5

Out of the brainstem, cross the cerebellopontine angle, through internal auditory meatus, into facial canal of temporal bone. Gives off severeal branches before exiting the skull through stylomastoid foramen

Question 6

Visceral efferent fibers of the facial nerve

Answer 6

• Superior salivary nucleus.
• Parasympathetic.
• Lacrimal gland, sublingual gland, submandibular gland

Question 7

Visceral afferent fibers

Answer 7

• Solitary nucleus
• Taste fibers
• Anterior 2/3 of the tongue

Question 8

Control of lower face muscles

Answer 8

Contralateral hemisphere

Question 9

Control of upper face muscles

Answer 9

Control from both hemispheres (bilateral representation)

Question 10

Facial muscles paralysed from lower motor neuron lesion

Answer 10

All facial muscles on affected side

Question 11

Facial paralysis in upper motor neuron lesion

Answer 11

Paralyses the muscles in the lower half of the face contralteral side

Question 12

Clinical examination of facial nerve

Answer 12

Facial muscles, taste, lacrimation/salvation

Question 13

Lesion location? unilateral involvement of lower face with normal eye closure

Answer 13

Contralateral supranuclear lesion

Question 14

Causes of contralateral supranuclear lesion

Answer 14

Vascular, tumor, demyelination, infection

Question 15

Lesion location? unilateral involvement of the upper and lower face with defective eye closure

Answer 15

Ipsilateral nuclear or infranuclear lesion

Question 16

Location where? bilateral involvement of upper and lower face

Answer 16

1. Bilateral nuclear lesions
2. Bilateral infranuclear lesions
3. Muscle disease

Question 17

Define Bell’s palsy

Answer 17

Acute paralysis of the face related to inflammation and swelling og facial nerve. Peripheral: ipsilateral, unilateral whole side

Question 18

Etiology of Bell’s palsy

Answer 18

Idiopathic, viral infections

Question 19

Clinical picture Bell’s palsy

Answer 19

1. Bell’s phenomenon: unable to close affected eye, eyeball rotates up and out, loss of eyebrow movement, dropp of lower lip
2. Pain over ipsilateral mastoid process
3. Taste impairment

Question 20

Treatment of Bell’s palsy

Answer 20

• High dose prednisolone 10 days
• Eye care (artificial tears)
• Protect affected eye

Question 21

Which branch of facial nerve is resposnible for taste?

Answer 21

Chorda tympani nerve

Question 22

Types of peripheral (lower motor neuron) facial nerve palsy

Answer 22

1. Bell’s palsy
2. Guillan Barré syndrome
3. Lyme
4. Infectious mononucleosis
5. HSV reactivation + Herpes Zoster

Question 23

Ramsey hunt syndrome

Answer 23

Hepres zoster infection of facial ggl. Severe pain, facial weakness.

• Affect CN facial and vestibulocochlear
• Fever
• Rash in the auditory canal + pinna
• Vertigo
• Sensorineural hearing loss

Question 24

Branches of facial nerve responsible for facial expression

Answer 24

Temporal, zygomatic, buccal, marginal mandibular, cervical

Question 25

Facial expression muscles

Answer 25

Auriculars
Corrugator supercilii,
Depressor anguli oris
Depressor labii inferioris
Levator labii superioris.
Mentalis
Nasalis
Occipitofrontalis
Orbicularis oculi
Orbicularis oris
Procerus
Risorius
Zygomaticus major and minor