Trigeminal Nerve - Mandibular Branch (V3)

Trigeminal Nerve - Mandibular Branch (V3)

• The mandibular branch (V3) is the largest of the three divisions of the trigeminal nerve.
• It exits the skull via the foramen ovale.
• It contains both sensory and motor fibers.
• It supplies various anatomical regions.

GDC Learning Outcomes

• Students need to describe relevant dental, oral, craniofacial, and general anatomy.
• This also includes explaining the application of this anatomy to patient management.

Intended Learning Outcomes

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

Resources

• Anatomy.tv
• Acland's Video Atlas of Human Anatomy
• Netter's Head and Neck Anatomy for Dentistry
• TeachMe Anatomy

Anatomical Course

• Shortly after leaving the skull, the V3 nerve divides into a smaller anterior trunk and a larger posterior trunk.
• Branches emerge from the nerve before division, including meningeal and nerve to medial pterygoid muscles.

Branches of V3

• Anterior Trunk Branches: Masseteric nerve, Deep temporal nerves, Nerve to lateral pterygoid muscle, and Long buccal nerve.
• Posterior Trunk Branches: Auriculotemporal nerve, Lingual nerve, and Inferior alveolar nerve.

Muscles of Mastication

• Medial Pterygoid Nerve (Motor): Enters the deep surface of the muscle. Also supplies tensor tympani & tensor veli palatini. Action: Elevates the jaw.
• Masseter: Masseteric nerve is the first branch of the anterior trunk. Crosses the masseter between coronoid process & condyle of mandible. Gives an articular branch to TMJ. Elevates the mandible.
• Temporalis: Anterior & deep temporal nerves. Elevates the mandible.
• Lateral Pterygoid: Nerve to lateral pterygoid may run part way with long buccal nerve. Depresses mandible.

Long Buccal Nerve

• The only sensory branch of the anterior trunk.
• Emerges between heads of lateral pterygoid. Runs along the lateral surface of the buccinator muscle in the cheek, close to the retromolar fossa of the mandible.
• Gives branches to the skin of the cheek.
• Pierces the buccinator to supply buccal sulcus & buccal gingivae of mandibular molars & premolars.

Auriculotemporal Nerve (A)

• First branch of the posterior trunk.
• Sensory.
• Autonomic to parotid gland due to fibers from otic ganglion.
• Two roots unite and run backwards under the lateral pterygoid muscle to lie between the condyle and sphenomandibular ligament.
• Emerges between TMJ & 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 facial nerve. Receives parasympathetic fibers for submandibular & sublingual glands.
• Emerges from under lateral pterygoid muscle and curves downwards & forwards between the ramus of mandible & 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 the mucosa covering anterior 2/3 dorsum of tongue, the under surface of the tongue, the floor of the mouth, and lingual gingivae of mandibular teeth.

Inferior Alveolar (Dental) Nerve

• Sensory and motor.
• Descends deep to lateral pterygoid muscle, behind the lingual nerve.
• Enters Mandibular Foramen.
• Travels in inferior dental or mandibular canal.
• Divides near premolars into mental nerve and incisive nerve.
• Mental nerve emerges at mental foramen & Incisive nerve runs anteriorly in incisive canal.

Branches of Inferior Alveolar Nerve

• Inferior Alveolar Nerve: Supplies mandibular molars & premolars & supporting structures (e.g., gingivae).
• Mental nerve: Supplies skin of chin, lower lip, and labial gingivae of anterior mandibular teeth.
• Incisive nerve: Innervates mandibular incisors & canines.

Mylohyoid Nerve (Branch of Inferior Alveolar Nerve)

• Given off just before the mandibular foramen.
• Runs in the mylohyoid groove to supply the mylohyoid muscle & the anterior belly of the digastric (motor).
• Depresses the mandible or elevates the hyoid (swallowing).

ID Nerve Block and Mental Nerve Block

• Diagrams and explanations of these dental procedures.

Trigeminal and Facial Nerve Examination

• Procedures for examining these nerves.

Summary

• The trigeminal nerve is the largest and 5th cranial nerve.
• It has three divisions: ophthalmic, maxillary, and mandibular.
• The mandibular nerve exits via the foramen ovale.
• The mandibular branch supplies mandibular teeth and supporting structures, anterior 2/3 of the tongue, the floor of the mouth and muscles of mastication.

Quiz

• A quiz to test student knowledge.

References

• List of resources used for the study notes.