The Mandibular Nerve Vc

10.1 Functions

The mandibular nerve is a mixed sensory and motor nerve. It transmits sensory fibres from the skin over the mandible, side of the cheek and temple, the oral cavity and contents, the external ear, the tympanic membrane and temporomandibular joint (TMJ). It also supplies the meninges of the cranial vault. It is motor to the eight muscles derived from the first branchial arch:

• temporalis, masseter

• medial, lateral pterygoids

• mylohyoid, anterior belly of digastric

• tensor tympani, tensor palati

As an aid to memory, note the four groups of two: tensors, pterygoids, big muscles and the last two in the floor of the mouth.

Some of its distal branches also convey parasympathetic secreto-motor fibres to the salivary glands, and taste fibres from the anterior portion of the tongue.

10.2 Origin, course and branches (Fig. 10.1)

• From trigeminal ganglion in middle cranial fossa.

• Infratemporal fossa with four main branches: inferior alveolar, lingual, auriculotemporal, buccal.

• Motor branches to muscles listed above.

Pons

Pons

Sensory fibres from mandibular nerve, cell bodies in trigeminal ganglion

Foramen ovale Buccal nerve

Trigeminal motor nucleus giving —

rise to branchiomotor fibres passing in mandibular nerve to first branchial arch muscles

Trigeminal motor nucleus giving —

rise to branchiomotor fibres passing in mandibular nerve to first branchial arch muscles

Cutaneous distribution:

Cutaneous distribution:

branches of buccal

Sensory fibres from mandibular nerve, cell bodies in trigeminal ganglion

Foramen ovale Buccal nerve

Lingual nerve Inferior alveolar nerve

Auriculotemporal nerve formed by two rootlets clasping middle meningeal artery

Note: other branches of mandibular nerve are small twigs to muscles

Auriculotemporal branches of buccal

Mental, continuation of inferior alveolar Fig. 10.1 Mandibular nerve.

Inferior alveolar nerve: lower teeth, skin, mylohyoid, digastric

Enters mandibular foramen, supplies lower teeth. Just before mandibular foramen, gives off nerve to mylohyoid and anterior belly of digastric, running in groove on medial aspect of mandible. Mental nerve emerges from mental foramen on anterior aspect of mandible to supply skin.

Lingual nerve: tongue sensation

Lingual nerve immediately below and medial to the third lower molar (wisdom) tooth. Passes forwards in floor of mouth, winding around submandibular duct. Supplies anterior tongue, gums. Conveys parasympathetic fibres from superior salivatory nucleus, and taste fibres to VII; these pass between lingual nerve and VII in chorda tympani (see Chapter 17).

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