Trigeminal Nerve - Mandibular Branch (V3)

Trigeminal Nerve - Mandibular Branch (V3)

• The trigeminal nerve is the largest cranial nerve.
• Knowledge of the trigeminal nerve is crucial for dental professionals.
• It has three divisions: ophthalmic (V1), maxillary (V2), and mandibular (V3).
• The mandibular branch (V3) is the largest of these divisions.
• It leaves the skull at the foramen ovale.
• It contains 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.
• Explain the relevance of the mandibular branch to dentistry.

What is supplied?

• Sensory:
  • Mandibular teeth and 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 (chewing)
  • Mylohyoid muscle
  • Anterior belly of digastric muscle
  • Tensor veli palatini muscle
  • Tensor tympani muscle

Anatomical Course

• Shortly after leaving the skull, the mandibular branch divides into a small anterior trunk and a larger posterior trunk.
• Branches before division include:
  • Meningeal branch
  • Nerve to the 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:
  • Enters the deep surface of the muscle
  • Supplies tensor tympani and tensor veli palatini
  • Action: elevates the jaw
• Masseter:
  • First branch of the anterior trunk
  • Crosses the mandible between the coronoid process and condyle
  • Gives an articular branch to the temporomandibular joint(TMJ)
  • Action: elevates the mandible (mouth closing)
• Temporalis:
  • Anterior and deep temporal nerves
  • Action: elevates the mandible (mouth closing)
• Lateral pterygoid:
  • Nerve may run part-way with the long buccal nerve
  • Action: depresses the mandible (mouth opening)

Long Buccal Nerve

• The only sensory branch of the anterior trunk.
• Emerges between the heads of the lateral pterygoid muscle.
• Runs on the lateral surface of the buccinator muscle.
• 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

• First branch of the posterior trunk.
• Has sensory function.
• Has autonomic connections to the parotid gland via the otic ganglion.
• Two roots unite and run backwards under the lateral pterygoid muscle, lying between the condyle and sphenomandibular ligament.
• Emerges between the temporomandibular joint (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.
• Receives parasympathetic fibers for submandibular and sublingual glands .
• Emerges from under the lateral pterygoid muscle, curving downward and forward between the ramus of the mandible and medial pterygoid muscle (pterygomandibular space).
• Lies anterior to, but deeper than, the inferior alveolar nerve.
• Passes toward 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 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.
• Supplies mandibular molars, premolars, and supporting structures (e.g., gingivae).
• Supplies skin of the chin, lower lip, and the labial gingivae of anterior mandibular teeth.
• Innervates mandibular incisors and canines.
• Mylohyoid nerve is a branch of the inferior alveolar nerve.
  • Given off before the mandibular foramen.
  • Runs in the mylohyoid groove.
  • Supplies the mylohyoid muscle and anterior belly of digastric muscle.
  • Action: Depresses the mandible

Nerve Blocks

• Information about different nerve blocks (e.g., inferior alveolar nerve block, mental nerve block).

Trigeminal and Facial Nerve Examination

• Description of examination procedures

Summary

• The trigeminal nerve is the largest of the cranial nerves.
• The trigeminal nerve has three divisions: ophthalmic, maxillary, and mandibular.
• Mandibular branch (V3) exits the skull through the foramen ovale.
• V3 supplies mandibular teeth, supporting structures, anterior two-thirds of the tongue, muscles of mastication, and more.