Infratemporal Fossa Flashcards
(21 cards)
What is the infratemporal fossa?
A space lying beneath the base of the skull between the side wall of the pharynx and the ramus of the mandible.
Also referred to as the parapharyngeal or lateral pharyngeal space.
What forms the medial boundary of the infratemporal fossa?
The lateral surface of the lateral pterygoid plate, the tensor palati muscle, and the superior constrictor.
The pterygo-maxillary fissure lies in front of the lateral pterygoid plate.
What is the lateral wall of the infratemporal fossa?
The ramus of the mandible and its coronoid process.
What is located at the anterior wall of the infratemporal fossa?
The posterior surface of the maxilla and the inferior orbital fissure above it.
What forms the roof of the infratemporal fossa?
The infratemporal surface of the greater wing of the sphenoid and the adjacent squamous part of the temporal bone.
The roof is perforated by the foramen ovale and foramen spinosum.
What is the posterior boundary of the infratemporal fossa?
The styloid process with the carotid sheath behind it.
What structures are contained within the infratemporal fossa?
- Deep part of the parotid gland
- Medial and lateral pterygoid muscles
- Insertion of temporalis into the coronoid process
- Maxillary artery and its branches
- Pterygoid venous plexus
- Mandibular nerve and its branches
- Otic ganglion
- Chorda tympani
- Posterior superior alveolar branches of the maxillary nerve.
What are the origins and insertions of the lateral pterygoid muscle?
Origin
Arises by two heads: upper from the roof of the infratemporal fossa, lower from the lateral surface of the lateral pterygoid plate.
Insertion
The two heads, lying edge to edge, converge and fuse into a short thick tendon that is inserted into the pterygoid fovea on the front of the neck of the mandible.
What is the action of the lateral pterygoid muscle?
Draws condyle and disc forwards from the mandibular fossa down the slope of the articular eminence.
Indispensable to active opening of the mouth.
What are the origins of the medial pterygoid muscle?
Arises by two heads: larger deep head from the medial surface of the lateral pterygoid plate, small superficial head from the tuberosity of the maxilla and pyramidal process of the palatine bone.
What is the action of the medial pterygoid muscle?
Closes the mouth and moves the mandible towards the opposite side in chewing.
What is the maxillary artery?
A terminal division of the external carotid artery that enters the infratemporal fossa.
How is the maxillary artery described conventionally?
In three parts: before, on, and beyond the lateral pterygoid muscle.
What are the five branches from the first part of the maxillary artery?
- Inferior alveolar
- Middle meningeal
- Accessory meningeal
- Two branches to the ear.
What does the inferior alveolar artery supply?
The pulps of the mandibular molar and premolar teeth and the body of the mandible.
What is the pterygoid plexus?
A network of very small veins around and within the lateral pterygoid muscle.
What does the pterygoid plexus drain into?
A short maxillary vein that joins the superficial temporal vein to form the retromandibular vein.
What is the sphenomandibular ligament?
A flat band of tough fibrous tissue extending from the spine of the sphenoid to the lingula and inferior margin of the mandibular foramen.
What structures pass between the sphenomandibular ligament and the neck of the mandible?
- Auriculotemporal nerve
- Maxillary artery
- Maxillary vein.
What are the nerve supply to lateral and medial pterygoid muscles?
Lateral pterygoid:
A branch from the anterior division of the mandibular nerve.
Medial pterygoid:
A branch from the main trunk of the mandibular nerve.
