1. Facial Nerve Palsy

2. Anatomy
Facial nerve is a mixed nerve, having a motor root and a sensory root
Motor root supplies all the mimetic muscles of the face which develop from the 2nd brachial arch 2

3. Anatomy
Sensory root “nerve of Wrisberg” carries taste fibers from the anterior 2/3 of the tongue and general sensation from the concha and retroauricular skin
Also it carries secretomotor fibers to the lacrimal, submandibular and sublingual glands as well as those in the nose and palate 3

4. Anatomy: Parts Intracranial part Intratemporal part Extracranial part4

5. Course of the Facial Nerve
Intracranial
Arises at the pontomedullary junction and courses with CNVIII to the internal acoustic meatus
12mm

6. Course of the Facial Nerve
Intratemporal
Meatal
Labyrinthe segment
Tympanic segment
Mastoid segment

7. Course of the Facial Nerve
Extracranial
From stylomastoid foramen to pesanserinus

8. Anatomy: Branches Greater superficial petrosal nerve
Nerve to stapedius
Chorda tympani
Comunicating branch
Posterior auricular nerve
Muscular branches
Peripheral branches: “Pes anserinus” 8

9. Presentation Functional and cosmetic problems
Upper lid fails to drop down and close
Lower lid loses tone and sags downward
May evert leading to ectropion
Produces lagophthalmos and consequent corneal exposure. 9

10. Presentation Interruption of the tear film Leads to drying of cornea
Ocular discomfort
Corneal ulcers
Infection
Perforation 10

11. Presentation Upper motor neurone (UMN)
can wrinkle their forehead (unless bilateral lesion)
Lower motor neurone (LMN)
can't wrinkle their forehead

12. House-Brackmann Facial Nerve Grading Scale
I. Normal
II. Mild dysfunction (slight weakness noticeable on close inspection)
III. Moderate dysfunction (obvious weakness, but not distinguishing differences between the two sides of the face)
IV. Moderately severe dysfunction (obvious weakness and disfigurement)
V. Only barely perceptive motor function
VI. Complete paralysis

13. Diagnosis History Presentation Hearing test Vestibular function
MRI / CT
Topognostic - Where is the lesion?
Qualitative -Degree of the lesion

14. Topodiagnostic Diagnosis
Schirmer’s tear test
Stapedius reflex
Taste test
Submandibular salivary flow test 14

15. Topodiagnostic Diagnosis

16. Qualitative Diagnosis
Nerve Excitability Test: NET
Maximum stimulation Test: MST
Electroneurography: ENoG
Electromyography: EMG 16

17. Bell’s Palsy
60-70% cases
Pathophysiology – Impaired “axoplasmic” flow from edema of facial nerve within fallopian canal
Rapid onset and evolution < 48 hours
May be associated with acute neuropathies of cranial nerves V- X
Pain or numbness affecting ear, mid-face, tongue and taste disturbances
Recurrences are more likely (2.5x) in patients with family history, immunodeficiency or diabetes

18. Pathophysiology
Main cause of Bell's palsy is latent herpes viruses (herpes simplex virus type 1 and herpes zoster virus), which are reactivated from cranial nerve ganglia.
Polymerase chain reaction techniques have isolated herpes virus DNA from the facial nerve during acute palsy. 18

19. Treatment Oral antivirals - Acyclovir Corticosteroid
Eye protection - lacrilube
Follow progression with serial exams
Facial nerve decompression
Progression to > 90% degeneration on ENOG
Performed before irreversible injury to the endoneurial tubules occurs (two weeks), will allow for axonal regeneration to occur

20. Herpes Zoster Oticus (Ramsay Hunt syndrome)

21. Herpes Zoster Oticus (Ramsay Hunt syndrome)
10-15% of acute facial palsy cases
Lesions may involve the external ear, the skin of EAC or soft palate
Associated symptoms – hearing loss, dysacusis and vertigo
Additional involvement of CN V, IX and X and cervical branches 2, 3 and 4
Pathogenesis – Neural injury due to edema at point between the meatal foramen and the geniculate fossa in the labyrinthe segment

22. Thanks！