Trigeminal Nerve Mandibular Branch (V3)

Trigeminal Nerve - Mandibular Branch (V3)

• The trigeminal nerve is the largest of the 5 cranial nerves.
• Knowledge about this nerve is important for dental professionals.
• The trigeminal nerve has 3 divisions: ophthalmic (V1), maxillary (V2), and mandibular (V3).
• The mandibular branch (V3) is the largest division.
• It exits the skull at the foramen ovale.
• This branch has both sensory and motor fibers.

Learning Outcomes

• Describe the function of the mandibular branch of the trigeminal nerve (CN V3).
• Outline the anatomical regions supplied by the mandibular branch (V3).
• Explain the relevance of the mandibular branch (V3) to dentistry.

What is Supplied?

• Sensory:

  • Mandibular teeth and their supporting structures
  • Mucosa of the anterior two-thirds of the tongue and floor of the mouth
  • Skin of the lower face
  • Parts of the temporal region and outer ear

• Motor:

  • Muscles of mastication
  • Mylohyoid
  • Anterior belly of digastric
  • Tensor veli palatini
  • Tensor tympani

Anatomical Course

• Shortly after exiting the skull, the nerve divides into a smaller anterior trunk and a larger posterior trunk.
• The nerve has branches before division:
  • Meningeal branch
  • Nerve to medial pterygoid muscle

Branches of V3

• Anterior Trunk Branches:

  • Masseteric nerve
  • Deep temporal nerves
  • Nerve to lateral pterygoid muscle
  • Long buccal nerve

• Posterior Trunk Branches:

  • Auriculotemporal nerve
  • Lingual nerve
  • Inferior alveolar nerve

Muscles of Mastication

• Medial Pterygoid Nerve (Motor):

  • Enters the deep surface of the muscle.
  • Supplies tensor tympani and tensor veli palatini.
  • Elevates the jaw.

• Masseter:

  • First branch of the anterior trunk.
  • Crosses between coronoid process and the condyle of the mandible.
  • Gives an articular branch to the TMJ.
  • Elevates the mandible (mouth closing).

• Temporalis

  • Anterior and deep temporal nerves
  • Elevates the mandible (mouth closing).

• Lateral Pterygoid

  • Nerve to lateral pterygoid may run part way with long buccal nerve
  • Depresses mandible (mouth opening).

Long Buccal Nerve

• The only sensory branch of the anterior trunk.
• Emerges between the heads of the lateral pterygoid and runs on the lateral surface of the buccinator muscle.
• Close to the retromolar fossa of the mandible
• Gives branches to the skin of the cheek.
• Pierces the buccinator to supply the buccal sulcus and buccal gingivae of mandibular molars and premolars.

Auriculotemporal Nerve (A)

• First branch of the posterior trunk.
• Sensory.
• Autonomic to the parotid gland due to fibers from the otic ganglion.
• Two roots unite and run backwards beneath the lateral pterygoid muscle.
• Between the condyle and sphenomandibular ligament.
• Emerges between the TMJ and the external auditory meatus.
• Finally ascends on the side of the head.

Lingual Nerve

• Second branch of the posterior trunk.
• Sensory.
• Unites with the chorda tympani branch of the facial nerve and receives parasympathetic fibers for the submandibular and sublingual glands.
• Emerges from under the lateral pterygoid muscle and curves downwards & forwards between the ramus of the mandible and medial pterygoid muscle.
• Lies anterior to but deeper than the inferior alveolar nerve.
• Passes towards the floor of the mouth.
• Twists around the submandibular duct and enters the tongue behind the sublingual salivary gland.
• Supplies:
  • Mucosa covering the anterior two-thirds of the tongue's dorsum
  • Under surface of the tongue
  • Floor of the mouth
  • Lingual gingivae of mandibular teeth

Inferior Alveolar (Dental) Nerve

• Sensory and motor.

• Descends deep to the lateral pterygoid muscle behind the lingual nerve.

• Enters the mandibular foramen.

• Travels in the inferior dental or mandibular canal in the mandible.

• Divides near the premolars into the mental nerve and incisive nerve.

• Mental nerve emerges at the mental foramen..

• Incisive nerve runs anteriorly in the incisive canal.

• Branches of Inferior Alveolar Nerve:

  • Mylohyoid nerve (B)
    • Given off just before the mandibular foramen.
    • Runs in the mylohyoid groove.
    • Supplies mylohyoid muscle and anterior belly of digastric (motor).
    • Depresses the mandible (on a fixed hyoid) or elevates the hyoid in swallowing.
  • Inferior Alveolar nerve:
    • Supplies mandibular molars and premolars and their supporting structures (e.g., gingivae).
  • Mental nerve:
    • Supplies skin of the chin, lower lip and labial gingivae of anterior mandibular teeth.
  • Incisive nerve:
    • Innervates mandibular incisors and canines.

Nerve Blocks

• ID Nerve Block
• Mental Nerve Block

Summary

• Trigeminal nerve is the largest of the 5 cranial nerves.
• Has 3 divisions (ophthalmic, maxillary and mandibular).
• Mandibular nerve exits via foramen ovale.
• Mandibular branch of trigeminal nerve supplies mandibular teeth, supporting structures, mucosa of anterior 2/3 of tongue, floor of mouth and muscles of mastication.

This quiz covers the anatomy and functions of the mandibular branch of the trigeminal nerve (CN V3). Learn about its sensory and motor supply, as well as its significance in dentistry. It’s essential for dental professionals to understand this crucial nerve for effective patient care.