Hygiene Atlas

Atlas · Plate I · Head and Neck Anatomy · 04

Cranial nerves

Twelve pairs of cranial nerves leave the brain, and the trigeminal (V) is the main sensory nerve of the face and teeth: V2 serves the maxillary teeth, V3 the mandibular teeth plus the chewing muscles. The facial nerve (VII) runs through the parotid to the muscles of expression, CN IX carries taste from the back third of the tongue, and CN XII moves the tongue.

High-yield facts · 11

  1. There are 12 pairs of cranial nerves; the trigeminal (V) is the largest and is the main sensory nerve of the face and teeth.S49
  2. V1 ophthalmic is sensory only; V2 maxillary is sensory only; V3 mandibular is both sensory and motor.S45
  3. V2 exits the skull through the foramen rotundum; V3 exits through the foramen ovale.S45
  4. V3 motor fibers supply mastication muscles plus mylohyoid, anterior digastric, tensor tympani and tensor veli palatini.S45
  5. The lingual nerve carries general sensation from the anterior two-thirds of the tongue and the lingual gingiva of mandibular teeth.S45
  6. The chorda tympani (VII) joins the lingual nerve and carries taste from the anterior two-thirds of the tongue plus parasympathetic fibers to the submandibular and sublingual glands.S49
  7. CN IX carries taste and general sensation from the posterior third of the tongue and parasympathetic supply to the parotid.S49
  8. CN XII is motor to the tongue; a lesion makes the protruded tongue deviate toward the injured side.S49
  9. CN VII exits through the stylomastoid foramen and splits into 5 branches inside the parotid: temporal, zygomatic, buccal, marginal mandibular, cervical.T4
  10. Bell's palsy is a CN VII paralysis that causes one-sided facial droop; transient VII paralysis can follow an IA block deposited too far posterior into the parotid.S15
  11. The long (buccal) nerve of V3 supplies the buccal gingiva of the mandibular molars.S69

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