THE FACIAL NERVE

1
??? ???? ?????? ??????
2
THE FACIAL NERVE
3
FACIAL NERVE FIBERS

• Motor
• to the stapedius and facial muscles
• Secreto-motor
• to the submandibular, sublingual salivary glands
  and to the lacrimal glands
• Taste
• from the anterior two thirds of tongue and palate
• Sensory
• from the external auditory meatus

4
ANATOMICAL DIVISIONS

• Intracranial
• Nuclei cerebellopontine
• Cranial (intratemporal)
• Meatal
• Fallopian canal ( labyrinthine, tympanic and
  mastoid )
• Extracranial (extratemporal)

5
THE INTRACRANIAL PART
1. The nucleui
6

• Upper motor lesions spare the upper facial
  muscles and affect the contralateral lower face

• Lower motor lesions affect all the ipsilateral
  facial muscles

7
UPPER MOTOR
LOWER MOTOR
8
Intracranial part (CP angle)
9
THE INTRA-TEMPORAL (CRANIAL)
10
(No Transcript)
11
THE EXTRACRANIAL PART
12
(No Transcript)
13
THE EXTRACRANIAL PART
14
FACIAL NERVE FIBERS

• Motor
• to stapedius, and facial muscles
• Secreto-motor
• to the submandibular, sublingual, and lacrimal
  glands
• Taste
• from the anterior two thirds of tongue and palate
• Sensory
• from the external auditory meatus

15
Distribution of facial nerve fibers
16
The secreto-motor and the taste fibres
17
VARIATIONS AND ANOMALIES
18
(No Transcript)
19
CLINICAL MANIFESTATIONS

• Paralysis of facial muscles
• Asymmetry of the face

20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
(No Transcript)
26
CLINICAL MANIFESTATIONS

• Paralysis of facial muscles
• Asymmetry of the face
• Inability to close the eye
• Accumulation of food in the cheek
• Phonophobia
• Dryness of the eyes
• Loss of taste

27
PATHOPHYSIOLOGY OF FACIAL NERVE INJURY
28
Neuropraxia (Conduction block)
Neurotmeses (Degeneration)
29
(No Transcript)
30
REGENERATION
31
Neuropraxia (Conduction block)
Neurotmeses (Degeneration)
32
(No Transcript)
33
Electrophysiological Tests

• Detect degeneration of the nerve fibers
• Useful only 48-72 hours following the onset of
  the paralysis

34
Electrophysiological Tests

• Nerve Excitability Test (NET)
• Electroneurography (ENoG)

35
Nerve excitability test (NET)

• The currents thresholds required to elicit
  just-visible muscle contraction on the normal
  side of the face are compared with those values
  required over corresponding sites on the side of
  the paralysis

36
Electroneurography (ENoG)

• The amplitude of action potentials in the muscles
  induced by the maximum current is compared with
  the normal side and used to calculate the
  percentage of intact axons.

37
(No Transcript)
38
Indications of Electrophysiological Tests

• In clinically complete facial paralysis to
  differentiate between conduction block
  (neuropraxia) and degeneration of nerve fibers
  (neurotmeses)

39
Interpretation of the tests

• Not useful in the first 48 72 hours
• After 48-72 hours (the time required for
  degeneration to take place)
• Normal results means that there is no
  degeneration (Neuropraxia)
• Abnormal results means degeneration

40
TOPOGNOSTIC TESTS

• Indicated in some cases to locate the site of the
  injury

41
TOPOGNOSTIC TESTS

• Schirmer's test
• Test the lacrimation function

42
TOPOGNOSTIC TESTS

• Schirmer's test
• Stapedial reflex
• Taste sensation

43
TOPOGNOSTIC TESTS

• Schirmer's test
• Stapedial reflex
• Taste sensation
• Salivary flow

44
CAUSES OF FACIAL PARALYSIS

• Congenital Birth trauma
• Traumatic Head and neck injuries surgery
• Inflammatory O.M, Necrotizing O.E., Herpes
• Neoplastic Meningioma, malignancy ear or parotid
• Neurological Guillain-Barre syndrome, multiple
  sclerosis
• Idiopathic Bells palsy

45
CAUSES OF FACIAL PARALYSIS

• Intracranial causes
• Cranial (intratemporal) causes
• Extracranial causes

46
Congenital Facial Palsy

• 80-90 are associated with birth trauma
• 10 -20 are associated with developmental
  lesions

47
INFLAMMATORY CAUSES OF FACIAL PARALYSIS
48
Facial Paralysis in AOM

• Mostly due to pressure on a dehiscent nerve by
  inflammatory products
• Usually is partial and sudden in onset
• Treatment is by antibiotics and myringotomy

49
Facial Paralysis in CSOM

• Usually is due to pressure by cholesteatoma or
  granulation tissue
• Insidious in onset
• May be partial or complete
• Treatment is by immediate surgical exploration
  and proceed

50
HERPES ZOSTER OTICUS (RAMSAY HUNT SYNDROME)

• Herpes zoster affection of cranial nerves VII,
  VIII, and cervical nerves
• Facial palsy, pain, skin rash, SNHL and vertigo

51
(No Transcript)
52
HERPES ZOSTER OTICUS (RAMSAY HUNT SYNDROME)

• Herpes zoster affection of cranial nerves VII,
  VIII, and other nerves
• Facial palsy, pain, skin rash, SNHL and vertigo
• Vertigo improves due to compensation
• SNHL is usually irreversible
• Facial nerve recovers in about 60
• Treatment by Acyclovir, steroid and symptomatic

53
Traumatic Facial Injury

• Iatrogenic
• Temporal bone fracture

54
Iatrogenic Facial Nerve Injury

• Operations at the CP angle, ear and the parotid
  glands

55
Temporal Bone Fracture

• Longitudinal
• Transverse

56
Transverse Fracture
57
Pathology

• Edema
• Transection of the nerve

58
Management of Traumatic Facial Nerve Injury

• If it is delayed in onset, it is usually
  incomplete and is due to edema
• Conservative
• If of immediate onset, it is usually complete and
  due to transection of the nerve
• Surgical repair

59
SURGICAL REPAIR
60
DIRECT ANASTOMOSIS
61
NERVE GRAFT
62
NERVE TRANSFER (ANASTOMOSIS)
63
MUSCLE FLAP
64
BELLS PALSY

• Most common diagnosis of acute facial paralysis
• Diagnosis is by exclusion

65
PATHOLOGY

• Edema of the facial nerve sheath along its entire
  intratemporal course (Fallopian canal)

66
ETIOLOGY

• Vascular vs. viral

67
CLINICAL FEATURES

• Sudden onset unilateral FP
• Partial or complete
• No other manifestations apart from occasional
  mild pain
• May recur in 6 12

68
PROGNOSIS

• 80 complete recovery
• 10 satisfactory recovery
• 10 no recovery

69
TREATMENT

• Reassurance
• Eye protection
• Physiotherapy
• Medications ( steroids, antivirals vasodilators)
• Surgical decompression in selected cases

70
SURGICAL MANAGEMENT

• Debate over years
• Patients with 90 degeneration
• Within 14 days of onset

71
THANK YOU