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Infratemporal Fossa and TMJ Joint


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Infratemporal fossa: INTRO
**inferomedial to temporal fossa, which is superior to zygomatic arch
**therefore medial to proximal ramus
**temporalis muscle arise form temporal fossa, coalesces and forms tendon deep to zygomatci arch to attach to coronoid process
IF fossa:
*between zygomatic arch and lateral pterygoid plate
*anterior: maxilla bone
*posterior: temporal bone; typanic plate of temporal bone and TMJ
*inferior: "hole in the floor"
*ceiling: greater wing of sphenoid and its foramina (ovale, spinosum); posterior extent: TMJ and styloid process; Superior: defect in which temporalis muscle travels from temporal fossa into IF-defect bordered by zygomatic arch and infratemporal crest
IF boundaries:
*medial: lateral pterygoid plate
*lateral: ramus of mandilbe
*superior: > wing of sphenoid adn infratemporal crest
*inferior: alveolar process of maxillary bone
*anterior: maxilla
*posterior: parts of temporal bone (styloid process)
IF communicates with other regions of skull:
1. orbit via inferior orbital fissure
2. pterygopalatine fossa medially via pterygomaxillary fissure
Primary contents of IF:
1. glenoid process of parotid gland
2. muscles of mastication: temporalis and pterygoid muscles
3. maxillary artery: main supply for IF, terminal branch of ECA
4. pterygoid venous plexus
5. mandibular nerve: main nerve of IF, V3 of trigeminal (V)
6. sphenomandibular ligament
Bony structures of attachment of mastication muscles:
1. lateral and medial pterygoid plates: from sphenoid
2. infratemporal crest: inferior, lateral edge of sphenoid
3. pyramidal process: of palatine bone
Parts of Mandible:
1. ramus
2. coronoid process
3. mylohyoid line
4. gonion: angle of mandible
5. lingula: tongue-like bony structure at level of mandibular foramen
Muscles of Mastication: Temporalis
*attaches to coronoid process and anterior aspect of mandilbe
*functions: 1)primary elevator, 2)primary retractor-specifically posterior, more horizontally inclined fibers
*closes jaw as in chewing
Muscles of Mastication:
*inserts on lateral surface of ramus and angle of mandilbe
*functions: 1)elevation, 2)clenching, 3)protrusion-via superficial fibers that come off external surface of zygomatic arch
*closes jaw as in biting
Muscles of Mastication:
Pterygoid muscles
1. lateral pterygoid
*more horizontal and has 2 heads: 1)superior head arises from infratemporal crest and inserts into disc between TMJ; 2)inferior head arises from lateral pterygoid plate and attaches into fovea of neck of mandible
*function: primary protruder

2) Medial pterygoid: runs along same angle as masseter does externally and has comparable attachment internally into angle of mandible
* 2 heads: 1)deep portion-arises from pterygoid plate, pyramidal process; 2)superficial-from tubercle of maxilla
*heads come together and insert into angle of mandible
*function: assist in elevation
Injury to nerve innervation muscles of mastication:
Present: 1) ipsilateral deviation of chin via muscle attachment of primarily pterygoid muscles; jaw swings toward that side (probably means V3 on that side is injured)
2) atrophy of temporal fossa and laterally, near the cheek (lack of masseter)
Maxillary Artery:
*primary artery of IF
*comes off ECA
*funs horizontally, deep to neck of mandible
*lateral to sphenomandibular ligament
**3 parts: 1st-mandibular; branches enter foramina/canals
2nd-pterygoid; muscular branches to muscles of mastication and buccinator
3rd-pterygopalatine; goes in/near pterygopalatine fossa
1st part of Maxillary Artery: Mandibular
1. deep auricular-pierce/enter external auditory canal
2. anterior tympanic-internal aspect of tympanic membrane/cavity
3. middle meningeal-travels up thru foramen spinosum
4. accessory meningeal-travels through foramen ovale; helps supply trigeminal ganglion and related meninges
5. inferior alveolar-descend into mandible and helps supply lower jaw
2nd part of Maxillary Artery: Pterygoid
1. masseteric
2. anterior deep temporal
3. posterior deep temporal
4. pterygoid
5. buccal
3rd part of Maxillary Artery: pterygopalatine
1. posterior superior alveolar-penetrates small foramina on posterior maxilla; supplies upper jaw/teeth
2. infraorbital-leaves infraorbital foramen onto face: terminal branch of maxillary
3. descending palatine-helps suppy hard and soft palate
4. artery of pterygoid canal
5. pharygeal branch
6. sphenopalatine-main blood supply to nasal cavity; terminal branch off maxillary
**chronic nose bleed (chronic epistaxis)-maxillary artery ligated (good collateral supply)
Pterygoid venous plexus:
1. maxillary vein
2. deep facial vein-from facial vein; can bring infection from paranasal region
3. one communication: inferior ophthalmic vein superiorly with caverous sinus
**can bring infection from external to internal
Mandibular Nerve (V3)
*main nerve of IF
*carries GSA and SVE
1. anterior division: primarily motor, except for buccal branch (sensory)
2. posterior division: primarily sensory, except for nerve to mylohyoid (innervates mylohyoid and anterior belly of digastric)
3. trunk: a) nerve to medial pterygoid (tensors); b)nervus spinosus (meningeal branch)
Mandibular nerve (cont)
*descends down through foramen ovale, into IF, and divides into inferior and posterior divisions
1. auricultemporal (ACT)-runs posteriorly, then ascends to external auditory meatus, posterior to superficial temporal artery; has loop proximally which allows middle meningeal artery to ascend
*sensory nerve to anterolateral portion of face, in front of ear
*carries some GVE from CNIX that will fall off in parotid for secretion
2. inferior alveolar nerve-gives off mental nerve
3. lingual
4. anterior and posterior deep temporal nerves-goes to temporalis
5.buccal branch-(long buccal) helps supply skin overlying cheek and mucosa lining adjacent area of oral cavity
Chorda tympani
*very small, chord-like nerve
*travels through middle ear
1. recurrent branch of facial nerve; branches off right before facial nerve exits stylomastoid foramen
2. enters middle ear, leaves cranium through petrotympanic fissure, and enters IF, then associates with lingual nerve
3. Both motor and sensory fibers in oral cavity:
a) motor fibers: preganglionic parasympathetic fibers from facial nerve; synapse on submandibular ganglion; make submandibular and sublingual glands salivate
b) fibers traveling back to brain stem are fiber of taste for anterior 2/3 of tongue
*(Anterior 2/3 have taste fibers conveyed by facial nerve and general sensation by lingual nerve)*
Otic Ganglion
*parasympathetic ganglion
*medial to V3 as it enters IF
*accepts preganglionic fibers of CNIX
*postganglionic fibers travel out with ACT nerve and on to parotid for salivation
1. facial nerve carries out salivation via submandibular and sublingual glands
2. CNIX carries out salivation via parotid gland
A. one of 2 synovial joints of head (other is between ear ossicles in middle ear)
B. modified hinge joint-both hinge and gliding action (gliding helps with protrusion of mandible)
C. lined with fibrocartilage instead of hyaline
D. articular disc interposed between 2 articular surfaces
TMJ: inferior view
1. mandibular fossa: cranial accepting cavity of TMJ
2. landmarks: zygomatic arch, styloid process, spine of sphenoid
3. articular tubercle (lateral protrusion) & articular eminence (horizontal portion)-forms bony anterior border of fossa
**tubercle doesn't articulate with anything; is site of attachment for lateral ligament of TMJ-helps stabilize lateral surface
ligaments of TMJ:
1. lateral ligament of TMJ
2. stylomandibular lig-thickening of parotid fascia; arises from styloid process of temporal bone and attaches to gonion
*TMJ closely related to external auditory meatus; condyle of mandible can ge driven into ear by fracturing anterior wall of EAC
3. sphenomandibular lig: a) remnant of Meckel's cartilage; b) arises form spine of sphenoid, adjacent to petrotympanic fissure; c) inserts on lingula of mandible; d) nerve to mylohyoid pierces SM lig
**Clinical: anesthesia in oral cavity -needle within lingula region (inferior alveolar nerve-lower teeth); piercing SM lig helps localize anesthesia around nerve and not spread to other V3 branches
TMJ dislocation:
1. medial: prevented by spine of sphenoid
2. posterior: prevented by tympanic plate and styloid process
3. dislocaton generally anterior to articular tubercle; head of condyle will jump over eminence
2 joint compartments of TMJ:
1. suprameniscal: protrusion (45-60%) and retraction
2. inframeniscal: elevation and depression
Middle cranial fossa:
1. trigeminal nerve
2. close to head of mandible: CC-force that comes up below angle of mandible could drive head into MCF (boxers)
Nerves: masseteric, ACT, great auricular
Blood: superficial temporal, middle meningeal, deep auricular, anterior tympanic, ascending pharyngeael

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