Infratemporal fossa and temporomandibular joint Flashcards Preview

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Flashcards in Infratemporal fossa and temporomandibular joint Deck (14)
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Contents of infratemporal fossa

-4 muscles of mastication
-Mandibular nerve (V3) and its branches
-Otic ganglion
-Chorda tympani
-Maxillary artery and branches
-Pterygoid plexus of veins


Osteology of infratemporal fossa

-The infra temporal fossa is below the zygomatic arch
-Superior boundary: greater wing of sphenoid, temporal bone, and zygomatic arch (zygomatic bone and temporal bone)
-Anterior boundary: zygomatic bone
-Posterior boundary: tempoal bone and styloid process
-Lateral boundary: zygomatic arch
-Medial boundary: maxilla and lateral pterygoid plate
-Parts of the mandible are within the infratemporal fossa


Osteology of the temporal fossa

-Above the zygomatic arch
-Includes the frontal, parietal, greater wind of sphenoid, and temporal bones


Osteology of the mandible

-Body: where molars are, contains the mental foramen for mental nerve (branch of inferior alveolar nerve of V3)
-Angle: roughly 90 degree turn of the mandible, connecting the ramus to the body
-Coronoid process: spike-like process anterior to the mandibular condyle (one attachment for temporal is muscle)
-Ramus: vertically running part of the mandible that contains the groove for mylohyoid nerve and the mandibular foramen (for inferior alveolar nerve), both on medial part of ramus
-Mandibular condyle: head of the mandible that inserts into TMJ
-Mental protuberance: most anterior part of mandible
-Mental tubercles: the two lateral sides of the mental protuberance


Muscles of mastication 1

-Masseter: attaches to the zygomatic arch and angle of the mandible
-Functions in elevation of mandible and protrusion
-Temporalis: attaches to the coronoid process from aponeurosis w/ occipitalis
-Functions in elevation and retraction (horizontal fibers)
-Lateral pterygoid: runs from greater wing of sphenoid and lateral wall of the lateral pterygoid plate to the articular disc and head of mandible
-Functions in depression and protrusion


Muscles of mastication 2

-Medial pterygoid: attaches to angle of mandible and medial wall of lateral pterygoid plate
-Functions in elevation and protrusion
-All of these muscles are innervated by branches of V3
-Both medial and lateral pterygoids are responsible for lateral movement of mandible
-The last 2 muscles of mastication are both innervated by mylohyoid nerve (branch of V3): mylohyoid and anterior belly of diagastric


Temporomandibular joint

-Articulation of condyle of mandible w/ mandibular fossa and the articular tubercle (eminence) of temporal bone
-Within the TMJ there is a lower and upper synovial space bordering both the condyle and the mandibular fossa/articular tubercle
-Btwn the two synovial spaces there is an articular disc
-Upper synovial space responsible for gliding action
-Lower synovial space responsible for hinge action
-Lateral pterygoid muscle opens mouth by pulling condyle onto articular tubercle, followed by hinging action of condyle on the tubercle in lower joint space


Dislocated jaw and TMJ d/o

-Dislocated jaw due to trauma or opening mouth too wide
-Condyles move anterior to articular tubercles and get caught there
-Must push up on anterior part of body and down on posterior part of body of the mandible
-TMJ d/o: pronounced joint noises associated w/ movement, pain upon palpation of muscles of TMJ, limited range of opening


Mandibular nerve in infratemporal fossa

-V3 has 4 vertical branches in infra temporal fossa and one horizontal branch
-Vertical branches from anterior to posterior (A BLIMP):
Buccal nerve, Lingual nerve, Inferior alveolar nerve, Mylohyoid nerve
-Horizontal branch of V3: auriculotemporal nerve
-Mylohyoid nerve branches off the inferior alveolar nerve and runs in the groove of the mylohyoid, while the inferior alveolar nerve enters the mandibular canal w/ the inferior alveolar artery


Components and innervation of V3 branches

-Buccal nerve (only SS) innervates mucosa of cheek and outer skin of the cheek
-Lingual nerve: SS to anterior 2/3rds of tongue, contains hitchhikers from VII via chord tympani (taste and para/pre)
-Inferior alveolar nerve: SS to lower teeth and skin of the chin (via mental nerve out of the mental foramen)
-Mylohyoid nerve: SM only to anterior belly of diagastric and mylohyoid muscles
-Mylohyoid nerve arose from inferior alveolar, so if inferior alveolar is tagged before the branching of mylohyoid it will have SM and SS
-Auriculotemporal nerve contains SS to skin of external ear/temple and hitchhikers from IX (para/post to parotid)


Hitchhikers onto V3 1

-Para/pre from VII: cell bodies in superior salivatory nucleus (VII) run w/ VII thru internal auditory meatus and branch off in chord tympani w/in the middle ear
-Taste fibers of VII have the same path to chord tympani
-From the middle ear chord tympani reaches the infra temporal fossa and joins w/ the lingual nerve soon after it branches off of V3
-The para/pre use lingual nerve to reach the submandibular ganglion than run to submandibular gland, some also jump back onto the lingual nerve to reach sublingual gland
-Therefore depending on if the lingual nerve is tagger before or after the submandibular ganglion it will have either para/pre or para/post
-The taste fibers run w/ lingual nerve all the way to the tongue and supply taste to anterior 2/3rds of tongue


Hitchhikers onto V3 2

-Para/pre from IX that reach the parotid gland via auriculotemporal have cell bodies in the inferior salivatory nucleus
-The axons run w/ IX thru the jugular foramen and then branch off IX to reach the middle ear as the tympanic nerve
-Tympanic nerve forms the tympanic plexus over the promontory of the middle ear
-This branch not only contains para/pre but also viscerosensory that will innervate all of the middle ear cavity
-The para/pre continue thru the middle ear as the lesser petrosal nerve and exit the middle ear thru foramen ovale


Hitchhikers onto V3 3

-Right after foramen ovale the para/pre synapses on the otic ganglion that resides next to V3
-From the otic ganglion the para/post fibers join the auriculotemporal nerve which runs to the parotid gland and the para/post provides innervation there
-After the gland the auriculotemporal nerve continues, but only w/ SS to skin of ear and temple
-Therefore if the auriculotemporal nerve is tagged after the gland (cutaneous branch), it has only SS
-But if it is tagged before the gland is has SS and para/post


Maxillary artery

-One of the terminal branches of the ECA, which terminate in infratemporal fossa
-The ECA terminates into the maxillary artery and the superficial temporal artery
-The maxillary gives off 2 important branches in the fossa: inferior alveolar artery and middle meningeal artery
-Inferior alveolar artery branches off inferiorly to run w/ inferior alveolar nerve thru mandibular foramen/canal
-Middle meningeal artery branches superiorly to run w/in a circle made by auriculotemporal nerve (perpendicular to each other) and up into the skull to supply the dura
-The three terminal branches of the maxillary artery: descending palatine, sphenopalatine, and infraorbital arteries

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