CN VII

• Disorders of CN VII

  Disorders of facial expression
• Conditions affecting CN VII - Peripheral nerve

  1. Hemifacial spasm - root zone

  2. Ramsey Hunt Syndrome - Geniculate ganglion

  3. Bells palsy - stylomastoid foramen distally
• CN VII

  • Innervates area of skin around external acoustic meatus and behind the ear
  • Anterior 2/3 of tongue taste sensation
  • General somatic innervation of deep tissues of face
  • Secreto-motor fibres to submandible and sublingual gland and also inner nose.
  • Reflexes - blinking, bright light corneal reflex (bilateral response)
• If Lacrimal gland in tact what would happen

  Watery eyes due to drooping
• When there’s drooping of mouth and if submandibular sublingual glands are in tact what happen

  Salivation
• Unilateral involvement of the lower face, with near normal eye closure

  • Indicates a contralateral supranuclear lesion = CONTRALATERAL UMNL
  • Vascular, tumour, demyelination + infection causes
• Unilateral involvement of upper + lower face, with defective eye closure

  • Indicates on ipsilateral nuclear infranuclear lesion =LMNL
• Peripheral Nerve

  • Unilateral weakness
  • May be localised to a specific muscle group
  • Parotid gland lesion -e.g. tumour or bleed
  • Parotid operations
  • Facial trauma -eg. blow to side of face
• Facial Canal = Stylomastoid foramen

  • Unilateral weakness
  • Cause = Fracture of skull base
  • Cause = Spread of middle ear infection
  • Cause = Bell's Palsy. Most Common
  • Cause = leukaemic deposits
  • Loss of taste and salivation - loss of Submandibular and sublingual glands
• Bell's Palsy

  • Rapid onset of facial muscle paresis + paralysis
  • 70% of patients fully recover
  • May have dyskinesis when nerve fibres grow into the wrong branch
  • Prednisone with 72 was high recovery rate
• Ramsay Hunt Syndrome

  • Continuous pain
  • Facial pain
  • Sharp pain inside car
  • Vesicular rash on external ear
  • LMN paralysis of facial nerve
  • Loss of taste over arterior 2/3 of tongue
  • Lasts around 3 weeks
  • Can involve other cranial nenes
  • Can develop persistent pain = post herpetic neuralgia
  • Take analgesics early on decreases risk
• Affecting CN VII at pons

  • Ipsilateral LMNL to face
  • Ipsilateral VI nerve palsy
  • Ipsilateral loss of pain + temp sensation (CNV)
  • Contralateral UMNL (limb weakness) = corticospinal tract
  • Contralateral decrease in touch, position + vibration
  • Contralateral decrease in pain + temp sensation
• Pathologies at pons

  • Vascular
  • Demyelination
  • Motor Neurone Disease
  • Syringobubia
  • Tumour
• Where on the face would an UMNL of CN VII affect

  Whole of the upper half of the face and the contralateral bottom quarter
• Where on the face would an LMNL of the CN VII affect

  One whole side of the face
• V, VIII (IX, X, XI) Nerve palsy

  • Loss of taste, salivation and lacrimation
  • Hyperacusis = increases loudness of sounds
  • Causes - acoustic tumours and meningioma