Sensory Innervation of the Ear

• • There are four cranial nerves and two upper cervical nerves that contribute to sensory innervation of the ear:
    • Cranial nerves:
      • V
      • VII
      • IX
      • X
    • Upper cervical nerves:
      • C2
      • C3
        • Though the sensory innervation to the ear may appear fairly well defined:
          • There is considerable overlap and ambiguity in the sensory distribution of these nerves

• The mandibular division of CN V (V3):
  • Supplies the:
    • Tragus
    • Helical crus
    • Anterosuperior wall of the external auditory canal
    • Adjacent tympanic membrane
    • Temporomandibular joint
  • The auriculotemporal branch but also has sensory nerve fibers via the lingual, buccal, and inferior alveolar nerves:
    • Which serve to innervate the:
      • Oral cavity:
        • Floor of mouth, lower teeth, palate, mandible including the temporomandibular joint (TMJ)
      • The three mayor salivary glands

Primary and referred otalgia pathways of the mandibular nerve (V3). Cranial nerve V is the most frequent pathway for referred otalgia via the auriculotemporal branch (Nerve of Arnold) of the trigeminal nerve.

• The facial nerve (VII) supplies the:
  • Posterior-inferior portion of the external ear canal
  • Adjacent tympanic membrane
    • The sensory distribution of the facial nerve is variable:
      • With an overlapping sensory distribution with the trigeminal nerve
    •  The seventh cranial nerve:
      • The posterior auricular nerve:
        • Serves to innervate the ear directly
      • The greater superficial petrosal nerve and the vidian nerve serve to supply the:
        • Nasal mucosa
        • Posterior ethmoid
        • Sphenoid sinuses
        • Soft palate

• The glossopharyngeal nerve (IX) supplies the:
  • Inner ear
  • Inner tympanic membrane
    • The tympanic nerve (Jacobson nerve, a branch of cranial nerve IX):
      • Directly innervates the ear but also has:
        • Pharyngeal, lingual, and tonsillar branches to supply the:
          • Posterior one-third portion of the tongue
          • Tonsillar fossa / pillars
          • Pharynx:
            • Inferior nasopharynx
          • Parapharyngeal space
          • Retropharyngeal space
          • Eustachian tube

• The vagus nerve (X) supplies:
  • A similar distribution to CN IX:
    • But also innervates the concha
  • The vagus nerve supplies the:
    • Valleculae
    • Lingual, and laryngeal surfaces of the epiglottis
    • Supraglottic larynx
    • Pyriform sinuses
    • Thyroid gland
    • More distant sites within the thorax:
      • Including the tracheobronchial tree and esophagus
  • The Arnold nerve:
    • Directly innervates the ear
  • The internal branch of the superior laryngeal nerve:
    • Innervate the larynx
  • The pharyngeal branch of the vagus nerve:
    • Innervate the lower pharynx

• The upper cervical nerves (C2 and C3) innervate:
  • The skin in front of and behind the ear
  • The medial and lateral aspect of the auricle
  • Temporomadibular joint
    • The upper cervical nerves (C2 and C3) innervate a significant portion of the external ear, including the auricle, lobule, and the skin in front of and behind the external ear via the:
      • Great auricular nerve
      • Lesser occipital nerves