Marginal mandibular branch of the facial nerve.

mandibular branch of the trigeminal nerve

The main motor portion of the facial nerve

The facial muscles are innervated by facial nerve (cranial nerve VII). In contrast, the nearby masticatory muscles are innervated by the mandibular nerve, a branch of thetrigeminal nerve (V).

The mandibular branch (V3) of the trigeminal nerve (CN V) runs down through the mandibular foramen to all the lower teeth. They need to be able to find that spot to properly numb the teeth of the mandible.