Mandibular nerve (V3): the lower division of the trigeminal
Quick facts
- Origin
- Third division of the trigeminal nerve (V3), leaves the skull through the foramen ovale.
- Type
- Mixed: sensory and motor. It is the only trigeminal division with motor fibers.
- Sensory territory
- Temple in front of the ear, cheek, lower lip, chin, lower teeth and tongue.
- Motor territory
- Muscles of mastication: masseter, temporalis and pterygoids.
The mandibular nerve, or V3, is the third and largest division of the trigeminal nerve. While the ophthalmic (V1) and the maxillary (V2) are purely sensory, V3 is mixed: it carries sensation from the lower third of the face and controls the muscles of mastication.
What does V3 supply?
On the sensory side, its branches cover areas that facial harmonization professionals know well. The auriculotemporal serves the area just in front of the ear and the posterior temple. The long buccal covers the cheek. The lingual supplies the tongue and floor of the mouth. The inferior alveolar runs into the mandible and ends as the mental nerve, which exits through the mental foramen and supplies the chin and lower lip.
On the motor side, V3 supplies the masseter, the temporalis, the pterygoids, the mylohyoid and the anterior belly of the digastric.
| Branch | Main function |
|---|---|
| Auriculotemporal | Sensation of the preauricular region and posterior temple |
| Long buccal | Sensation of the cheek |
| Lingual | Sensation of the tongue and floor of the mouth |
| Inferior alveolar and mental | Lower teeth, chin and lower lip |
| Motor branches | Masseter, temporalis, pterygoids and others |
Why does it matter in practice?
- Toxin in the masseter: the masseter's motor command comes from V3. The toxin acts at the neuromuscular junction and reduces muscle contraction without injuring the nerve. The decision on volume and technique belongs to the qualified professional, after assessment, according to the rules of their professional council (in Brazil).
- Numbness of the chin and lower lip: territory of the mental nerve, a branch of V3. If it appears with no clear cause after an oral or mandibular procedure, it calls for reassessment.
- Anesthesia: blocks in the mandibular region reach branches of V3. Numbness of the tongue and lip for hours is expected, and the patient should be warned.
- Preauricular and TMJ pain: the auriculotemporal nerve relates to the joint region, and pain there can have a muscular or joint origin.
How does V3 fit into planning?
The lower third is the part of the face with the most players: bone, strong muscles, fat and vessels. Knowing that the same nerve controls the bite and supplies sensation to the chin helps connect symptoms the patient describes as if they were unrelated, for example "pain when chewing" and "tingling lip".
Also called: mandibular division of the trigeminal, V3, nervus mandibularis.
Frequently asked questions
What is the difference between V1, V2 and V3?
V1 supplies the forehead and nose, V2 the middle third and V3 the lower third. Only V3 also carries motor commands, to the muscles of mastication.
Is the mandibular nerve related to toxin in the masseter?
Yes. The masseteric branch of V3 controls the masseter. The toxin blocks the neuromuscular junction of that muscle, without injuring the nerve.