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Infratemporal Fossa 2

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Borders of infratemporal fossa
Superior to the zygomatic arch.

Medial and inferior to the temporal fossa.

Medial (deep) to the zygomatic arch and to the proximal ramus.

Posterior to the maxilla.

Anterior to temporal bone, TMJ and styloid process.

Ceiling is formed by greater wing of the sphenoid bone and it's foramina (ovale and spinosum)

Floor is partially missing, anteriorly the aveolar process of maxillary bone.
Temporalis Muscle
Arises from the infratemporal fossa. Forms a tendon deep to the zygomatic arch that attaches to the coronoid process.

Muscle of mastication.

Innervation from V3, deep temporal branches.
Infratemporal communications with other regions of the skull
With orbit via inferior orbital fissure

With the pterygopalatine fossa medially via pterygomaxillary fissure
Contents of the infratemporal fossa
Part of the parotid gland
Muscles of mastication (temporalis and pterygoid muscles)
Maxillary artery
Pterygoid venous plexus
Sphenomandibular ligament
Bony structures for attachment of mastication muscles
Lateral and medial pterygoid plates: parts of the sphenoid bone
Infratemporal crest: inferior, lateral edge of the sphenoid bone.
Pyramidal process of the palatine bone
Masseter Muscle
Muscle of mastication

Attaches to inferior border and medial surface of maxillary process of zygomatic bone and zygomatic arch.

Attaches to angle and lateral surface of ramus of mandible.

Innervated by masseteric nerve (V3).

Elevates mandible, protrudes mandible, clenches jaw.
Lateral Pterygoid
Muscle of mastication

Two heads - (1) from infratemporal surface and crest of greater wing of sphenoid bone and (2) lateral surface of lateral pterygoid plate.

Attaches to joint capsule and articulate disc of TMJ, pterygoid fovea on anteriomedial aspect of neck of condyloid process of mandible.

Innervated by nerves to lateral pterygoid (V3)

Protracts mandible and depresses ching, swings jaw to side, big lateral chewing movements. Primary protruder.
Medial Pterygoid
Muscle of mastication

Runs at the same angle as the masseter

Attaches to (1) medial surface of lateral pterygoid plate and pyramidal process of palatine bone and (2) tuberosity of maxilla.

Attaches to medial surface of ramus of mandible, inferior to mandibular foramen.

Innervated by nerve to medial pterygoid (V3)

Acts with masseter to elevate mandible, protrustion, small grinding movements.
What is the primary artery of the infratemporal fossa?
Maxillary Artery from the external carotid artery.

Runs horizontally, deep to the head of the mandible. Lateral to the sphenomandibular ligament.
What are the three parts of the maxillary artery?
1st Part: Mandibular. Branches enter foramina/canals.

2nd Part: Pterygoid. Muscular branches to muscles of mastication and buccinator.

3rd Part: Pterygopalatine. Goes to things in or near pterygopalatine fossa.
Branches from the 1st/mandibular portion of the maxillary artery
Deep auricular- pierce/enter the external auditory meatus

Anterior tympanic- travel up to the internal aspect of tympanic membrane/tympanic cavity

Middle meningeal- travels up through the foramen spinosum

Accessory meningeal- travels through forman ovale; helps supply the trigeminal ganglion and related meninges.

Inferior alveolar- descends and travels into the mandible and helps supply the lower jaw.
Branches from the 2nd/pterygoid portion of the maxillary artery
Branches to muscles:

Masseteric

Anterior deep temporal

Posterior deep temporal

Pterygoid

Buccal
Branches from the 3rd/pterygopalatine portion of the maxillary artery
Posterior superior alveolar- penetrates small foramina on posterior maxilla; help supplies the upper jaw/teeth

Infraorbital- leaves infraorbital foramen out onto the face; terminal branch of maxillary artery.

Descending palatine - helps supply the hard & soft palate, and adjacent areas

Artery of pterygoid canal

Pharyngeal branch

Sphenopalatine- main blood supply of the nasal cavity; terminal branch off maxillary artery. Patients with chronic nose-bleeds (chronic epistaxis) will have their maxillary artery ligated. Good collateral blood supply between both sides allows this. Some have even had their entire external carotid artery ligated.epistaxis.
Pterygoid venous plexus
Surrounds the arterial branches.

Tributaries: Maxillary vein. Deep facial vein from facial vein. Connection with cavernous sinus via inferior opthalmic vein. Route for infection.
Mandibular Nerve (V3)
Main nerve of the Infratemporal Fossa

Passes through foramen ovale

GSA and SVE

Sensory innervation to mucosa of anterior 2/3 of the tongue, floor of mouth, inferior oral vestibule, mandibular teeth, skin of lower lip, buccal, parotid, temporal regions of the face, external ear.

Motor innervation to muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani.
Anterior and posterior branches of the mandibular nerve (V3)
Divides in the infratemporal fossa.

Anterior: Primarily motor except for buccal branch (sensory).

Posterior: Primarily sensory except for nerve to mylohyoid (to mylohyoid and anterior belly of digastric).
Trunk of Mandibular nerve (V3)
Branches to medial pterygoid and Nervus spinosus (meningeal branch)
Auriculotemporal nerve
Branch from Mandibular (V3) nerve.

GSA.

Runs posteriorly, then ascends to external auditory meatus, posterior to the superficial temporal artery. The ACT nerve has a loop proximally, which allows the middle meningeal artery (transverses foramen spinosum) to ascend through it.

Sensory to anterior-lateral portion of the face.

Some GVE fibers from Glossopharyngeal (IX) nerve catch a ride to get to the parotid gland (secretomotor).
Which nerve does the middle meningeal artery ascend through?
The auriculotemporal nerve, which forms a loop around the nerve.
Inferior alveolar nerve
Branch from mandibular (V3) nerve.

GSA.

Enters the mandible via the mandibular foramen, travels through the mandibular canal where it supplies the mandibular teeth with sensory branches. Gives of mental nerve which exits via mental foramen to supply the skin of the chin and lower lip.
Lingual nerve
Branch from the mandibular nerve (V3)

GSA

Medial and anterior to inferior alveolar nerve.

Supplies the mucosa of the anterior 2/3 of tongue.
Buccal Branch from V3
Sensory to skin overlying cheek and mucosa lining adjacent area of the oral cavity.
Submandibular ganglion
Situated above the deep portion of the submaxillary gland, on the hyoglossus, near the posterior border of the Mylohyoideus, and is connected by filaments with the lower border of the lingual nerve.

Receives a branch from the chorda tympani nerve which runs in the sheath of the lingual; these are sympathetic efferent (presynaptic) fibers from the facial nucleus or the superior salivatory nucleus of the medulla oblongata that terminate in the submandibular ganglion.

The postsynaptic fibers pass to the submaxillary gland, it communicates with the sympathetic by filaments from the sympathetic plexus around the external maxillary artery.
Chorda Tympani
Small branch from the facial nerve (in the facial canal) that travels through the middle ear. Leaves the cranium through the petrotympanic fissure, and enters the infratemporal fossa. Once in the IF, it becomes associated with the lingual nerve.

Hitchhiking fibers of the chorda tympani are both taking motor fibers into the oral cavity and bringing sensory fibers back from the oral cavity.

Motor fibers- bringing preganglionic parasympathetic fibers from the facial nerve; will later synapse on the submandibular ganglion. The postganglionic fibers make submandibular & sublingual gland salivate.

Fibers in chorda tympani traveling back to the facial nerve/brain stem are fibers of taste for the anterior 2/3 of the tongue. Anterior 2/3 of tongue has sensation by lingual nerve and taste by facial nerve.
Otic Ganglion
Parasympathetic ganglion just inferior to the foramen ovale. Medial to V3.

Preganglionic fibers from glossopharyngeal nerve (IX). Postganglionic travel with auriculotemporal nerve to parotid gland.
Which nerves innervate the salivary glands?
Facial Nerve (VII) to submandibular and sublingual glands.

Glossopharyngeal nerve (IX) to parotid gland.
What are the two synovial joints in the head?
TMJ and between the ossicles in the middle ear.
What type of movements does the TMJ have?
Modified hinge joint. Hinge and gliding action.
What is the articular turbrecle?
Doesn't articulate with anything!

Lateral ligament of the TMJ attaches to it.

Helps stabilize lateral surface of articulation.
Stylomandibular ligament
Thickening of parotid fascia. Arises from styloid process and attaches into the gonion.
Sphenomandibular (petrotympanic) ligament
Ligament on the Medial surface to help stabilize the TMJ.

Remnant of Meckel's cartilage.

Arisses from the spine of the sphenoid bone, inserts into lingula on the mandible.

Putting a needle through the SM ligament allows doctor to localize anesthesia around just the inferior alveolar nerve.
What are the two joint compartment of the TMJ?
Suprameniscal: Above disc. Protrusion and retraction.

Inframeniscal: Below disc. Elevation and depression.
Spehnomeniscus Muscle
Part of the lateral pterygoid muscle but we won't consider it a different muscle.

Attaches into the disc of the TMJ. Pulls disc forward at the joint moves forward so the bones always have something between them.
TMJ Nerves and vessles
Nerves: Masseteric, auriculotemporal, great auricular.

Blood supply: Superficial temporal artery, middle menigial artery, deep auricular, anterior tympanic, ascending pharyngeal.

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