Lecture 9- CN 7, Facial Nerve Flashcards Preview

HESP 632 - Medical Audiology > Lecture 9- CN 7, Facial Nerve > Flashcards

Flashcards in Lecture 9- CN 7, Facial Nerve Deck (36)
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1
Q

What are the different segments of the facial nerve?

A
  • Brainstem
  • Pontine
  • Meatal
  • Labyrinthine
  • Tympanic
  • Mastoid
  • Extratemporal
2
Q

What are the different components of the facial nerve?

A
  • Branchial motor (special visceral efferent)
  • Visceral motor (general visceral efferent)
  • Special sensory (special afferent)
  • General sensory (general somatic afferent)
3
Q

What is the branchial motor component of the facial nerve?

A
  • Supplies the muscles of facial expression
  • Posterior belly of digastric muscle
  • Stylohyoid and stapedius
4
Q

What is the visceral motor component of the facial nerve?

A

Parasympathetic innervation of the lacrimal, submandibular, and sublingual glands, as well as mucous membranes of nasopharynx, hard and soft palate

5
Q

What is the special sensory component of the facial nerve?

A

Taste sensation from the anterior 2/3 of tongue; hard and soft palates

6
Q

What is the general sensory component of the facial nerve?

A

General sensation from the skin of the concha of the auricle and from a small area behind the ear

7
Q

What is the posterior auricular branch?

A

Pulls ears back, pulls scalp back

8
Q

What is the temporal branch?

A

Pulls ear forward and raises ear, moves scalp forward, moves eyebrows medially and down

9
Q

What is the temporal and zygomatic branch?

A

Closes eyelids and creases skin around eye

10
Q

What is the zygomatic and buccal branch?

A

Elevates upper lip, upper corner of the mouth and nasolabial folds

11
Q

What is the buccal branch?

A

Mouth movements, flares nostrils

12
Q

What is the marginal mandibular branch?

A

Pulls skin of chin up

13
Q

What is the cervical branch?

A

Pulls down at corner of the mouth

14
Q

What is differential diagnosis for acute facial nerve paralysis?

A
  • Polyneuritis
  • Trauma
  • Otitis media
  • Sarcoidosis
  • Melkersson-Rosenthal
  • Neurologic disorders
15
Q

What is differential diagnosis for chronic or progressive facial nerve paralysis?

A
  • Malignancies
  • Benign tumors
  • Cholesteatoma
16
Q

What should examination of a patient with facial paresis/paralysis consist of?

A

History

  • Time of onset
  • Precipitating factors
  • Speed of progression
  • Associated symptoms

Physical examination
- House-Brackmann classifications

Topodiagnostic

Electrophysiologic tests

Lab tests PRN

Imaging

17
Q

What are the grades of the House-Brackmann scale?

A

Grade I: Normal

Grade II: Mild

Grade III: Moderate

Grade IV: Moderately severe

Grade V: Severe

Grade VI: Total Paralysis

18
Q

What is grade I of the House-Brackmann scale?

A

Grade I: Normal

19
Q

What is grade II of the House-Brackmann scale?

A

Gross: slight weakness noticeable on close inspection

At rest: normal symmetry and tone

Motion:

  • Forehead: moderate to good
  • Eye: complete closure with minimum effort
  • Mouth: slight asymmetry
20
Q

What is grade III of the House-Brackmann scale?

A

Gross: obvious but not disfiguring asymmetry; may have hemifacial spasm

At rest: normal symmetry and tone

Motion:

  • Forehead: slight to moderate movement)
  • Eye: complete closure with effort
  • Mouth: slightly weak with maximum effort
21
Q

What is grade IV of the House-Brackmann scale?

A

Gross: obvious weakness and/or disfiguring asymmetry

At rest: normal symmetry and tone

Motion

  • Forehead: no movement
  • Eye: incomplete closure
  • Mouth: asymmetric with maximum effort
22
Q

What is grade V of the House-Brackmann scale?

A

Gross: only barely perceptible motion

At rest: asymmetry

Motion:

  • Forehead: no movement
  • Eye: incomplete closure
  • Mouth: slight movement
23
Q

What is grade VI of the House-Brackmann sclae?

A

No movement

24
Q

What are topodiagnostic tests of facial nerve function?

A
  • Schirmer’s Test of Lacrimal Function
  • Stapedial Reflex
  • Electrogustometry
  • Salivary Flow
25
Q

What is the nerve excitability test?

A

Transcutaneous stimuli delivered over stylomastoid foramen.

Electrical pulses delivered at increasing current levels until facial twitch is noticeable.

26
Q

What is the maximum excitability test?

A

Transcutanteous stimuli looking for twitch.

Increase current to get maximum response.

27
Q

What is electromyography (EMG)?

A

Recording of spontaneous and voluntary muscle potentials.

Needle electrodes in facial muscle groups.

May help to predict recovery.

28
Q

What is electroneuronography (ENoG)?

A
  • Stimulating electrodes deliver suprathreshold electrical stimuli
  • Recording electrode measures compound muscle action potential
  • Reduction in response amplitude reflects number of damaged motor fibers
  • Best 3 days to 3 weeks
29
Q

What is the prognostic value of ENoG?

A

> 90% degeneration at 3 weeks- surgery

<90% degeneration at 3 weeks- chance for good recovery

30
Q

What is the presentation of Herpes Zoster Oticus?

A
  • Severe pain
  • Vesicles in concha
  • Severe (grade V and VI) facial paralysis
  • Frequently involves CN VIII giving hearing loss and vertigo
  • May involve CN V, IX, X, XI, and XII
31
Q

What is the cause of herpes zoster oticus?

A

Varicella zoster virus

32
Q

What is the prognosis of herpes zoster oticus?

A
  • Spontaneous recovery of CN VII function 22-31%

- ENoG prognositcation (not so good)

33
Q

What are the treatment options for Herpes Zoster Oticus?

A
  • Acycolvir ++
  • Prednisone ?
  • MCF decompression not justified
34
Q

What are the presentations of a facial neuroma?

A
  • Facial weakness
  • Hearing loss in 50%
  • 10-15% have tinnitus, ear canal mass, pain, vestibular Sx, and otorrhea
35
Q

What are some pediatric facial nerve disorders?

A
  • Congenital paralysis
  • Prenatal acquired paralysis
  • Postnatal acquired paralysis
  • Mobius syndrome
  • Hemifacial microsomia
  • Prenatal acquired paralysis
36
Q

What are some postnatal acquired pediatric facial nerve disorders?

A
  • Osteopetrosis - Albers-Schonbergs disease

- Melkersson- Rosenthal syndrome