Anatomy of the Infratemporal Fossa Flashcards
Where is the infratemporal fossa situated?
What are its boundaries?
- found deep to and inferior to zygomatic arch
- deep to ramus of mandible
- posterior to maxilla
- communicates with temporal fossa
Boundaries:
- lateral: ramus of mandible
- superior: zygomatic arch
- posterior: tympanic plate and mastoid process
- anterior: posterior aspect of maxilla
- medial (internal): lateral pterygoind plate
- inferiorly: where medial pterygoind muscle attaches to mandible
What muscles are within the infratemporal fossa?
Nerves?
Arteries?
Veins?
Muscles:
- temporalis (inferior part)
- medial pterygoid
- lateral pterygoid
Nerves:
- branches of mandibular nerve CN V3: auriculotemporal, inferior alveolar, lingual and buccal
- chorda tympani of CN VII
- otic ganglion
Arteries: maxillary artery and its branches
Veins: pterygoid plexus
What is the function of the lateral pterygoid?
Origin:
Insertion:
Innervation:
- Opens jaw
Origin:
Superior head - infratemporal crest of greater wing of sphenoid
Inferior head - lateral surface of lateral pterygoid plate
Insertion:
- Mandibular pterygoid fovea
- TMJ capsule and articular disc
Innervation:
- CN V3 - nerve to lateral pterygoid
What is the function of the medial pterygoid?
Origin?
Insertion?
Innervation?
- Jaw closer
Origin:
Deep head: medial surface of lateral pterygoid plate
Superficial head: tuberosity of maxilla
Insertion: medial surface of mandibular ramus
Innervation: CN V3 - nerve to medial pterygoid
What is the network of veins in the infratemporal fossa and where does it form?
What are its tributaries, and where do they drain to?
What is its clinical relevance?
Pterygoid venus plexus forms around the lateral pterygoid muscle and completely surrounds the maxillary artery.
Tributaries:
- facial vein and deep facial veins which drain into maxillary vein which drains towards retromandibular veins
Clinical relevance:
Communication with cavernous sinus, where superior and inferior opthalmic veins drain into, therefore spread of infection through venous sinuses into cranial cavity
How is the maxillary artery split up?
1st part: before lateral pterygoid
2nd part: associated with lateral pterygoid
3rd part: after lateral pterygoid
Name the branches of the 1st part of the maxillary artery, before lateral pterygoid:
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- Deep auricular
- anterior tympanic
- middle meningeal
- accessory middle meningeal
- inferior alveolar
Name the branches of the 2nd part of maxillary artery, associated with lateral pterygoid muscle:
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- deep temporal
- masseteric branches
- pterygoid branches
- buccal branch
Name the branches of the 3rd part of maxillary artery, after lateral pterygoid:
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- sphenopalatine
- descending palatine
- posterior superior alveolar
- infra-orbital
- pharyngeal branches
- vidian (artery of pterygoid canal)
Name the important branches of the maxillary artery:
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- Middle meningeal (in cranial vault via foramen spinosum)
- inferior alveolar (supplys lower teeth)
- deep temporal
- buccal
- sphenopalatine (nose/palate)
- infra-orbital (upper teeth and skin of mid face)
- posterior superior alveolar (upper teeth)
When/where do the sensory and motor fibres unite?
What do they divide into?
- once the motor and mandibular sensory root pass through foramen ovale, they unite together, outside of the cranial cavity and divide into an anterior and posterior parts
Name the branches of the anterior mandibular division:
- deep temporal: motor innervation of the temporalis
- buccal: sensory innervation to mucosa and skin of cheek
- muscular branches: motor innervation to masseter and lateral pterygoid
Name the nerves of the posterior division of CN V3:
- auriculotemporal nerve: sensory to tragus and posterior temple
- inferior alveolar: sensory to lower dental arch and mandibular labial gingivae
- nerve to mylohyoid: motor to mylohyoid and ABD
- mental nerve: sensory to chin, lower lip mucosa and gingivae of lower 3-3
- lingual nerve: sensory to anterior 2/3rds of tongue, FOM and mandibular lingual gingivae
What does the otic ganglion supply?
Where is it situated and explain its path:
Where do the presynaptic fibres come from?
- parasympathetic secretomotor innervation to the parotid gland from CN IX
- it is situated just below foramen ovale and ‘hitches a ride’ on auriculotemporal branch of CN V3 to the parotid gland
- from glossopharyngeal CN IX to otic ganglion
What is the chorda tympani and which foramen does it pass through?
What does chorda tympani carry?
Which cranial nerve does it hitch a ride with?
Chorda tympani is a branch of the facial nerve and passes through the internal acoustic meatus, then exits just before stylomastoid foramen.
- parasympathetic innervation and special sensation of taste to the anterior 2/3rds of tongue and the submandibular and sublingual salivary glands
- CN V3 - lingual nerve branch
Where do the following nerves innervate?
a) buccal
b) mental
c) dental branches of IAN
d) incisive
e) lingual
a) buccal - supplies buccal mucosa/gingivae of molars
b) mental - buccal gingivae of anteriors and premolars
c) dental branches of IAN - posterior teeth
d) incisive - incisors and canines
e) lingual - lingual gingivae, FOM and anterior 2/3rds of tongue
