Corpus: Mandibular nerve

The mandibular nerve is the third terminal branch of the fifth cranial nerve (V3) and carries both somatosensory and special visceral motor fibers.

After the mandibular nerve passes the trigeminal ganglion, it exits the cranial cavity through the foramen ovale. Here, it picks up the motor root and enters the infratemporal fossa, where it divides into its terminal branches.

The fibers that run to the masticatory muscles are sometimes referred to collectively as the masticatory nerve.

3.1. Sensory branches

3.1.1. Meningeal branch

The meningeal branch re-enters the cranial cavity as the spinosal nerve from the infratemporal fossa through the foramen spinosum and supplies the dura mater and the mucosa of the mastoid air cells with sensation.

3.1.2. Auriculotemporal nerve

The auriculotemporal nerve receives postganglionic fibers from the otic ganglion, which provide parasympathetic innervation to the parotid gland. It then encircles the middle meningeal artery and delivers these fibers to the parotid gland. It also supplies sensation to the skin in the temporal region and in front of the auricle.

3.1.3. Inferior alveolar nerve

The inferior alveolar nerve enters the mandibular canal between the medial and lateral pterygoid muscles and supplies the teeth and gingiva of the lower jaw with sensation. Its terminal branches are the incisive nerve and the mental nerve. The mental nerve innervates the skin of the chin and the lower lip.

3.1.4. Lingual nerve

The lingual nerve also runs between the medial and lateral pterygoid muscles. It receives preganglionic fibers and taste fibers from the chorda tympani. It delivers preganglionic fibers to the submandibular ganglion, which then supplies the submandibular and sublingual glands with postganglionic fibers. The lingual nerve also provides general sensory and special sensory fibers to the anterior two-thirds of the tongue, adjacent gingiva, and the soft palate.

3.1.5. Buccal nerve

The buccal nerve passes through the buccinator muscle and supplies the mucosa of the cheek and the gingiva in the area of the molars.

3.2. Motor branches

3.2.1. Mylohyoid nerve

The mylohyoid nerve supplies the mylohyoid muscle and the anterior head of the digastric muscle.

3.2.2. Masseteric nerve

The masseteric nerve supplies the masseter muscle.

3.2.3. Deep temporal nerves

The deep temporal nerves provide motor innervation to the temporalis muscle.

3.2.4. Pterygoid nerves

The pterygoid nerves supply the medial and lateral pterygoid muscles with motor innervation. The medial pterygoid nerve also carries fibers to the tensor tympani muscle.

3.2.5. Additional motor branches

Through two additional motor branches, the mandibular nerve supplies the tensor veli palatini muscle, which tenses the soft palate, and the tensor tympani muscle, which reduces sound conduction. Fine branches also run to the otic ganglion.

Damage to the branches that innervate the masticatory muscles leads to a deviation of the lower jaw toward the side of the damaged nerve when the mouth is opened. This deviation is due to the failure of the muscles that move the jaw medially.