Nerves of the Infratemporal Region

Nerves of the Infratemporal Region

A) Mandibular division of the trigeminal nerve

• Passes through the foramen ovale and innervates the tensor veli palatini and tensor tympani muscles, muscles of mastication (temporalis, masseter, and lateral and medial pterygoid), anterior belly of the digastric muscle, and the mylohyoid muscle.
• Provides sensory innervation to the lower teeth and to the lower part of the face below the lower lip and the mouth.

Gives rise to the following branches:

1. Meningeal branch

• Accompanies the middle meningeal artery, enters the cranium through the foramen spinosum, and supplies the meninges of the middle cranial fossa.

2. Muscular branches

• Include masseteric, deep temporal, medial pterygoid, and lateral pterygoid nerves.
• Innervate the corresponding muscles of mastication.

3. Buccal nerve

• Descends between the two heads of the lateral pterygoid muscle.
• Innervates skin and fascia on the buccinator muscle and penetrates this muscle to supply the mucous membrane of the cheek and gums.

4. Auriculotemporal nerve

• Arises from two roots that encircle the middle meningeal artery.
• Innervates sensory (general somatic afferent [GSA]) branches to the temporomandibular joint.
• Carries postganglionic parasympathetic and sympathetic general visceral efferent (GVE) fibers to the parotid gland in addition to GSA fibers.
• Has terminal branches that supply the skin of the auricle and the scalp.

5. Lingual nerve

• Descends deep to the lateral pterygoid muscle, where it joins the chorda tympani , which conveys the parasympathetic preganglionic (secretomotor) fibers to the submandibular ganglion and taste fibers from the anterior two thirds of the tongue.
• Lies anterior to the inferior alveolar nerve on the medial pterygoid muscle, deep to the ramus of the mandible.
• Crosses lateral to the styloglossus and hyoglossus muscles, passes deep to the mylohyoid muscle, and descends lateral to and loops under the submandibular duct.
• Supplies general sensation for the anterior two thirds of the tongue.

6. Inferior alveolar nerve

• Passes deep to the lateral pterygoid muscle and then between the sphenomandibular ligament and the ramus of the mandible.
• Enters the mandibular canal through the mandibular foramen and supplies the tissues of the chin and lower teeth and gum.

Gives rise to the following branches:

• Mylohyoid nerve, which innervates the mylohyoid and the anterior belly of the digastric muscle.
• Inferior dental branch, which innervates lower teeth.
• Mental nerve, which innervates the skin over the chin.
• Incisive branch, which innervates the canine and incisor teeth.

B) Otic ganglion

• Lies in the infratemporal fossa, just below the foramen ovale between the mandibular nerve and the tensor veli palatini.
• Receives preganglionic parasympathetic fibers that run in the glossopharyngeal nerve, tympanic plexus, and lesser petrosal nerve and synapse in this ganglion.
• Contains cell bodies of postganglionic fibers that run in the auriculotemporal nerve to innervate the parotid gland.

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