CN IX-XII

• Lower CN palsies

  Rarely occur in isolation
• CN IX (Glossopharyngeal nerve)

  • Efferent: Stylopharyngeus -> pharyngeal plexus
  • Preganglionic parasympathetic to parotid gland (salivation)
  • Gag Reflex

  Afferent: Sensory to posterior 1/3 tongue (taste, touch, nociception), Eustachian tube, carotid sinus to CNS

  
  

  Pathology - glossopharyneal neuralgia
• CN X (Vagus nerve)


  Efferent: Motor to thoracic/abdominal viscera, larynx, pharynx, soft palate

  Afferent: Sensory from larynx, pharynx, trachea, thoracic/abdominal viscera, external auditory meatus
• Clinical features of CN X palsy

  • Hoarse voice,
  • reduced vocal strength,
  • weak cough,
  • nasal quality of speech,
  • nasal regurgitation,
  • dysphagia,
  • pain/altered sensation in external auditory meatus,
  • reduction in control of circulatory system,
  • poor digestion
• CN XI (Accessory nerve)


  Efferent: Innervates trapezius and sternocleidomastoid muscles

  Afferent: Possibly some sensory from muscles supplied, mainly from C3+4 via cervical plexus
• Clinical features of CN XI palsy


  • Weakness and difficulty turning head, difficulty with shoulder movement
• CN XII (Hypoglossal nerve)


  Efferent: Innervates muscles of the tongue
• Clinical features of CN XII palsy


  • Weakness of tongue muscles, difficulty swallowing, deviation of tongue to weak side when sticking it out
• Lower cranial nerve palsies rarely occur in isolation, often present as syndromes
• Cranial nerve syndromes

  • Vernet's Syndrome (IX, X, XI)
  • Collet Sicard Syndrome (IX, X, XI, XII)
  • Villaret's Syndrome (IX, X, XI, XII + Horner's syndrome)
• Wallenberg's Syndrome


  Involves corticospinal tract, cerebellar peduncles, can present with cerebellar symptoms

  No cure, symptoms include nausea, vomiting, sometimes hiccups
• Why do lower cranial nerve lesions rarely occur in isolation?

  Mainly due to the fact that they all run closely together and a mass lesion is likely to affect multiple nerves