infratemporal fossa Flashcards
boundaries of temporal fossa
- superior: superior temporal line
- inferior: zygomatic arch
- anterior: zygomatic process of frontal bone and frontal process of zygomatic bone
- posterior: supramastoid crest
*Boundaries of the infratemporal fossa
- lateral: ramus of the mandible
- anterior: maxilla
- medial: lateral pterygoid plate
- roof: greater wing of sphenoid
- posterior: open
temporalis muscle
origin: temporal fossa, fascia and inbetween 2 temporal lines
insertion: coronoid process (apex, medial surface, anterior border until external oblique line of the mandible)
nerve supply: from deep temporal nerves; 1st branchial arch (from 1st pharyngeal arch V3)
action: elevation (by anterior fibers) and retraction (by posterior fibers) of the mandible
masseter
origin: inner surface and lower border of zygomatic arch (superficial–maxillary process; deep–whole length of zygomatic arch)
insertion: outer surface of ramus (superficial–lower part of ramus; deep–lateral surface of rams superior to superficial)
nerve supply: massetric nerve (branch from anterior division of V3 and passes mandibular notch
action: elevation and protraction of mandible
lateral pterygoid
origin: upper head–infratemporal surface and greater wing of sphenoid
lower head–lateral surface of lateral pterygoid
plate
Insertion: neck of mandible and articular disc of TMJ
Action: 1. pulls neck of mandible forward with articular disc to depress mandible and open mouth
2. acts with medial pterygoid of same side during movement of chewing (moving mandible to opposite side)
3. acts with medial pterygoid to protrude the mandible
medial pterygoid
Origin: superficial head–tuberosity of maxilla
deep head–medial surface of lateral pterygoid plate
Insertion: angle of the mandible (medial surface)
Nerve supply: main trunk of mandibular nerve (V3)
Action: elevates mandible, acting with lateral pterygoid during movement of chewing and protraction
pterygomandibular space
- located b/w medial pterygoid medially and mandibular ramus laterally
- contains inferior alveolar nerve (IAN) and artery (IAA) and lingual nerve (LN)
- communicates with parapharyngeal space posteriorly (infection here could be dangerous)
depression of mandible
lateral pterygoid digastric geniohyoid mylohyoid platysma
elevation
temporalis
masseter
medial pterygoid
protrusion
lateral and medial pterygoids of both sides
retraction
posterior fibers of temporalis
lateral chewing movement
lateral and medial pterygoids of both sides acting alternately
all muscles of mastication are protractors EXCEPT —-
Temporalis
all muscles of mastication are elevators EXCEPT —
lateral pterygoid
mandibular nerve
- arises from trigeminal ganglion in the middle cranial fossa
- immediately receives the motor root of the trigeminal nerve (sensory and motor)
- leaves cranium through the foramen ovale into the infratemporal fossa
- contains GSA (general somatic afferent) and SVE (spatial visceral efferent) fibers
- branches of CN V3 supply the four muscles of mastication but not the buccinator (supplied by facial nerve)
what’s the only muscular branch from posterior division of trigeminal?
nerve to mylohyoid
trunk of the mandibular nerve supplies?
medial pterygoid, tensor tympani, tensor palatini
anterior division of CN V supplies what muscles?
temporalis
lateral pterygoid
masseter
long buccal nerve supplies
only sensory division of anterior trigeminal
skin, mucous membrane, gum around buccinator
lingual nerve supplies
anterior 2/3 of tongue
general sensory?
what CN joins with lingual nerve and supplies taste, submandibular gang and sublingual gang?
CN VII
chorda tympani
what nerve goes through the mental foramen
inferior alveolar nerve
mylohyoid nerve supplies
mylohyoid muscle and anterior belly of digastric
auriculotemporal nerve supplies
auricle, temporal region, TMJ, parotid (sensation)
lesser superficial petrosal nerve joins —– to supply parotid gland
auriculotemporal (general visceral efferent)
CN going through ovale and forms otic ganglion
CN IX
three groups of branches in infratemporal fossa
- trunk
- anterior branches
- posterior branches
branches arising from trunk in infratemporal fossa
- Spinous nerve: passes through the spinous foramen and enters the cranium. It is a sensory nerve innervating the dura mater
- Medial pterygoid nerve: innervates the medial pterygoid muscle, tensor veli paltini, tensor tympani
anterior branches in infratemporal fossa
buccal nerve (sensory)
masseteric nerve
deep temporal nerve
lateral pterygoid
posterior branches in infratemporal fossa
auriculotemporal nerve
lingual nerve
inferior alveolar nerve
auriculotemporal nerve
- supplies sensory fibers to the auricle and temporal region
- sends articular (sensory) fibers to TMJ
- conveys postsynaptic parasympathetic secretomotor fibers from the otic ganglion to parotid gland
inferior alveolar nerve
enters mandibular foramen and passes thru mandibular canal –> inferior dental plexus–> sends branches to all mandibular teeth on its side
terminal branch of inferior alveolar nerve
mental nerve
passes through mental foramen
lingual nerve
sensory to anterior two thirds of tongue, floor of mouth, and lingual gingivae
chorda tympani nerve and submandibular ganglion
- branch of CN VII carrying TASTE from anterior two thirds of the tongue
- joins lingual nerve in infratemporal fossa
- also carries secretomotor fibers to submandibular and sublingual salivary glands
- *parasympathetic
otic ganglion
parasympathetic
- location: infratemporal fossa, just inferior to foramen ovale
- presynaptic parasympathetic fibers: derived mainly from the glossopharyngeal nerve (via lesser pet nerve) synapse in the otic ganglion
- postsynaptic parasympathetic fibers: secretory to parotid gland, pass from the otic ganglion to this gland thru auriculotemporal nerve
roots of otic ganglion
parasympathetic (functional) root: lesser superficial petrosal nerve
sensory root: auriculotemporal nerve
sympathetic root: postganglionic fibers from the superior cervical ganglion
injury to inferior alveolar nerve
loss of teeth/lower lip sensation
lingual nerve injury
after third molar removal
- nerve position is lateral to retromolar pad
maxillary artery
- arises posterior to neck of mandible as larger of two terminal branches of external carotid
- three parts:
1. mandibular: deep to condyle of mandible
2. pterygoid: superficial or deep to lateral pterygoid muscle
3. pterygopalatine: inside infratemporal fossa (extends to pterygopalatine fossa)
branches of 1st part of maxillary artery
MIADA
- Middle meningeal (to dura mater and calvaria)
- Inferior alveolar artery (to mandibular gingiva and teeth)
- Anterior tympanic artery (to tympanic membrane)
- Deep auricular (to external acoustic meatus)
- Accessory meningeal artery (to cranial cavity)
branches of 2nd part of maxillary artery
(muscular branches)
- deep temporal artery (to temporal muscle)
- pterygoid artery ( to pterygoid muscles)
- masseteric artery (to massetor)
- buccal artery (to buccinator muscle)
branches of 3rd part of maxillary artery
- posterior superior alveolar artery
- infra-orbital artery
- greater palatine artery
- pharyngeal artery
- sphenopalatine artery
- artery of the pterygoid canal
* Collectively, these branches supply the nasal cavity, roof of the oral cavity, and all upper teeth. ALSO contribute to blood supply of sinuses, oropharynx, and floor of orbit
middle meningeal artery and extradural hematoma
- first part of maxillary artery (origin: petrous part of internal carotid)
- ascends between two roots of auriculotemporal nerve to enter cranial cavity through foramen spinosum
- divides into anterior and posterior
- anterior ascends opposite the pterion and posterior branch runs posteriorly toward the tentorium cerebelli
- supplies dura, trigeminal ganglion, and pertosal branch that supplies facial nerve
- common source of extradural hemorrhage and hematoma and plays a role in development of migrane
clinical course of extradural hematoma
- initial loss of consciousness following head trauma
- temporary recovery of consciousness (lucid interval)
- renewed decline in mental status (talk and die)
epidural hematoma
- traumatic rupture of middle mengingeal artery
- lucid interval, then loss of consciousness, headache, hemiplegia
- biconvex, hyperdense lesion located between the brain and calvarium, limited by suture lines
- manage by surgical drainage
subdural hematoma
- rupture of bridging vein
- increasing headache over days or weeks
- changes in mental status
- cresent-shaped homogenous lesion between brain and calvarium, not limited by suture lines
- manage by surgical drainage
subarachnoid hemorrhage
- secondary to rupture of saccular aneurysm
- trauma
- sudden, severe headache
- loss of consciousness
- extensive area of hyperdense signals around circle of willis
- manage by medical therapy to reduce vasospasm
- surgical intervention: clippingor endovascular repair
pterygoid venous plexus
- located between temporalis and pterygoid muscles
- venous plexus equivalent of most of maxillary artery
- maxillary vein corresponds to first of the artery and pterygoid plexus to second and third part of artery
pterygoid plexus may provide alternative path for ______ and ______ in case of internal jugular vein obstruction
intracranial venous blood and CSF
pterygoid plexus connects ____ with ____ through emissary veins that pass through ______ and with ophthalmic veins through ______
facial veins with cavernous sinus (cranial cavity) through emissory veins that pass thru foramen ovale and with ophthalmis veins thru inferior orbital fissure
**dangerous triangle
explain transantral approach to pterygopalatine fossa
- approach through maxillary sinus
- elevate upper lip
- traverse the anterior wall of maxilla
- chip away the posterior wall
- go through anterior wall of pterygopalatine fossa
**ligates the maxillary artery to control the chronic bleeding from the nose (epistaxis–nasal bleeding)
