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بسم الله الرحمن الرحيم

بسم الله الرحمن الرحيم. THE FACIAL NERVE. 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

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بسم الله الرحمن الرحيم

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  1. بسم الله الرحمن الرحيم

  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. Lower motor lesions affect all the ipsilateral facial muscles • Upper motor lesions spare the upper facial muscles and affect the contralateral lower face

  7. UPPER MOTOR LOWER MOTOR

  8. Intracranial part (CP angle)

  9. THE INTRA-TEMPORAL (CRANIAL)

  10. THE EXTRACRANIAL PART

  11. THE EXTRACRANIAL PART

  12. 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

  13. The secreto-motor and the taste fibres

  14. VARIATIONS AND ANOMALIES

  15. CLINICAL MANIFESTATIONS • Paralysis of facial muscles • Asymmetry of the face

  16. 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

  17. PATHOPHYSIOLOGY OF FACIAL NERVE INJURY

  18. Neuropraxia (Conduction block) Neurotmeses (Degeneration)

  19. REGENERATION

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

  21. Electrophysiological Tests • Nerve Excitability Test (NET) • Electroneurography (ENoG)

  22. Nerve excitability test (NET) • The current 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

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

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

  25. 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

  26. TOPOGNOSTIC TESTS • Indicated in some cases to locate the site of the injury

  27. TOPOGNOSTIC TESTS • Schirmer's test • Test the lacrimation function

  28. TOPOGNOSTIC TESTS • Schirmer's test • Stapedial reflex • Taste sensation

  29. TOPOGNOSTIC TESTS • Schirmer's test • Stapedial reflex • Taste sensation • Salivary flow

  30. 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: Bell’s palsy

  31. CAUSES OF FACIAL PARALYSIS • Intracranial causes • Cranial (intratemporal) causes • Extracranial causes

  32. Congenital Facial Palsy • 80-90% are associated with birth trauma • 10 -20 % are associated with developmental lesions

  33. INFLAMMATORY CAUSES OF FACIAL PARALYSIS

  34. 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

  35. 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”

  36. 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

  37. 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

  38. Traumatic Facial Injury • Iatrogenic • Temporal bone fracture

  39. Iatrogenic Facial Nerve Injury • Operations at the CP angle, ear and the parotid glands

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