Mandibular nerve
Introduction • Largest of the 3 division of trigeminal nerve ( mandibular , opthalmic ,maxillary) • Nerve of the first branchial arch • Mixed nerve
Course and relation • Originates in middle cranial fossa thru a
large sensory and a small motor root • Trigeminal ganglion in its lateral part gives rise to sensory division and motor div arises deep to it • Leaves the fossa thru foramen ovale • Main trunk lies in infratemporal fossa and then divides into small ant and large post trunk
Branches
• Main trunk
• Meningeal br • Nr to medial pterygoid • Anterior trunk • Buccal nr (s) • Massetric • Deep temporal • Lateral pterygoid • Posterior trunk • Auriculotemporal • Lingual • inf alveolar
Mandibular nerve
Anterior division • Masseteric branches • Posterior and anterior temporal
branches to the temporalis muscle • The nerve to the medial pterygoid • The nerve to the lateral pterygoid • The buccal nerve
The buccal nerve of V3 • passes between the 2 heads of the lateral
pterygoid muscle. • continues into the cheek on the lateral surface of the buccinator muscle. • is the terminal branch of the anterior division • is sensory to the mucosa of the inside of the cheek and the lower gums around the molar teeth. • does not supply the motor innervation of the buccinator.
Posterior division:
Auriculotemporal nerve: • leaves V3 just inferior to the foramen ovale and projects • • • •
posteriorly in the infratemporal fossa parallel to the roof. The initial segment encircles the middle meningeal artery as the artery ascends to enter the foramen spinosum and receives postganglionic parasympathetic fibers from the otic ganglion which are secretomotor to the parotid gland. Passes medial to the head of the mandibular condyle and sends a sensory branch to the TMJ. Enters the deep portion of the parotid gland giving sensory branches as well as parasympathetic postganglionic fibers from the otic ganglion. Its terminal portion accompanies the superficial temporal artery and innervates the upper half of pinna of the ear and part of the temporal region (Pain and general sensation).
Inferior alveolar (dental) nerve • From the foramen ovale to the mandibular foramen on the medial
aspect of the ramus of the mandible, lying between the medial and lateral pterygoid muscles and just posterior to the lingual nerve (Clemente plate 478; Grant p. 585 fig. 7.63; Netter 41). • The branch to mylohyoid and to the anterior belly of the digastric is the only branch in the infratemporal fossa. It first lies in the mylohyoid groove, and then on the inferior aspect of the mylohyoid to reach the digastric muscle (Clemente plate 479; Grant p. 653, fig. 8.13; Netter 41). • The portion of the inferior alveolar nerve in the ramus of the mandible is entirely sensory to lower teeth, lower gums and the mucosa of the lower lips. • It exits the mandible as the mental nerve (Clemente plate 542; Grant p. 536, fig. 7.13; Netter 41) to innervate the mucosa and gum adjacent to the lower lip.
Lingual nerve • lies anterior to the inferior alveolar nerve and remains medial to mandible. • receives the chorda tympani in the infratemporal fossa. The chorda
tympani reaches the infratemporal fossa via the petrotympanic fissure . The chorda tympani contains preganglionic parasympathetic secretomotor fibers of VII from the tympanic plexus and special sensory fibers for taste from the anterior 2/3 of the tongue. The taste fibers have their cell bodies in the geniculate ganglion of VII. • Terminal distribution of the lingual nerve and associated fibers which mediate general sensation (pain, touch temperature and pressure) is to the floor of the mouth and the anterior 2/3 of the tongue.
Applied anatomy • Examination of mandible nerve by clenching the teeth • Referred pain • Mandibular neuralgia
Mandibular block technique: • Injection of anesthetic is performed in
the fascial compartment defined by the fascial covering of the medial pterygoid and the medial aspect of the ramus of the mandible • The anesthetic diffuses to the lingual and inferior alveolar nerves.