The Mandibular Division of the Trigeminal Nerve (CNV3)

Anatomical Course

The mandibular nerve contains both sensory and motor fibres:

• Sensory fibres – arise from three sensory nuclei (the mesencephalic, principal sensory, and spinal nuclei of the trigeminal nerve).
• Motor fibres – arise from the motor nucleus of the trigeminal nerve.

The motor root runs along the floor of the trigeminal cave, beneath the trigeminal ganglion, and joins the sensory root before leaving the cranium through the foramen ovale.

After emerging from the skull, the mandibular nerve enters the infratemporal fossa, where it divides into four branches – the auriculotemporal nerve, buccal nerve, inferior alveolar nerve and lingual nerve.

By TeachMeSeries Ltd (2026)

Fig 1
Overview of the distribution of the trigeminal nerve and its terminal branches

Auriculotemporal Nerve

The auriculotemporal nerve arises from the trigeminal nerve as two roots:

• Superior somatosensory root – contains sensory fibres.
• Inferior parasympathetic root – contains post-ganglionic parasympathetic fibres from the glossopharyngeal nerve

The two roots pass on either side of the middle meningeal artery before uniting.

The parasympathetic fibres originate from the glossopharyngeal nerve and synapse in the otic ganglion before joining the auriculotemporal nerve. The sensory fibres pass through the ganglion without synapsing.

Buccal Nerve

The buccal nerve is a sensory branch of the mandibular nerve. From its origin, it passes between the two heads of the lateral pterygoid muscle before coursing anteriorly.

It supplies sensory innervation to the buccal mucosa (cheek) and the buccal gingiva (gums) of the mandibular molar and premolar teeth. It does not supply the dental pulp.

Inferior Alveolar Nerve

The inferior alveolar nerve is predominantly sensory. Shortly after branching from the mandibular nerve, it gives rise to the mylohyoid nerve – which carries motor fibres to the mylohyoid muscle and the anterior belly of the digastric muscle.

The remaining sensory fibres enter the mandibular canal, where the nerve supplies the mandibular teeth. It then emerges through the mental foramen as the mental nerve, which provides sensory innervation to the lower lip and chin.

By TeachMeSeries Ltd (2026)

Fig 2
Anatomical course of the inferior alveolar and lingual nerves. Note the close proximity of the two nerves. The portion of the inferior alveolar nerve that runs through the mandibular canal has been removed.

Lingual Nerve

This branch of the trigeminal nerve carries general sensory axons. It also acts as a conduit for special sensory and autonomic fibres belonging to the chorda tympani, a branch of the facial nerve (CN VII).

General sensory fibres innervate the anterior two-thirds of the tongue, as well as the mucus membrane lining its undersides.

The special sensory fibres carry on with the lingual nerve to provide taste to the anterior two-thirds of the tongue.

The autonomic fibres branch to synapse in the submandibular ganglion, eventually innervating the submandibular and sublingual glands.

By TeachMeSeries Ltd (2026)

Fig 3
The submandibular ganglion.

Sensory Functions

The mandibular nerve provides sensory innervation to structures derived from the first pharyngeal arch. This includes sensation from the lower third of the face, the mandibular teeth and gingiva, and the anterior two-thirds of the tongue.

Sensory innervation is distributed between the terminal branches of the nerve as follows:

• Auriculotemporal nerve – skin of the temporal region, anterior auricle, external acoustic meatus, and tympanic membrane
• Buccal nerve – buccal mucosa and buccal gingiva of the mandibular molar and premolar teeth
• Inferior alveolar nerve – mandibular teeth, lower lip, and chin
• Lingual nerve – general sensation to the anterior two-thirds of the tongue and the mucous membrane of its inferior surface

Taste sensation from the anterior two-thirds of the tongue is not supplied by the mandibular nerve itself, but by the facial nerve. These special sensory fibres travel with the lingual nerve via the chorda tympani to reach the tongue.

By TeachMeSeries Ltd (2026)

Fig 4
Cutaneous innervation to the head and

Motor Functions

The mandibular nerve is the only branch of the trigeminal nerve to carry motor fibres. It supplies the muscles of mastication:

• Masseter
• Medial pterygoid
• Lateral pterygoid
• Temporalis

In addition to these, the mandibular nerve innervates several other muscles, including the tensor tympani, tensor veli palatini, anterior belly of the digastric, and the mylohyoid.

Autonomic Functions

The trigeminal nerve has no autonomic nucleus and does not give rise to autonomic fibres directly. However, its branches carry autonomic fibres from two other cranial nerves to their target organs:

Chorda Tympani and Lingual Nerve

The chorda tympani arises from the facial nerve and carries preganglionic parasympathetic fibres. These fibres join the lingual nerve and synapse in the submandibular ganglion, before supplying the submandibular and sublingual salivary glands.

Glossopharyngeal Nerve & Auriculotemporal Nerve

Parasympathetic innervation of the parotid gland originates from the glossopharyngeal nerve. Postganglionic fibres from the otic ganglion are carried to the gland by the auriculotemporal nerve.