9.2 The TMJ and Infratemporal Fossa Flashcards
What is the temporomandibular joint?
Articulation between the mandibular fossa, the articular tubercle and the head of the manbible allowing movements of the jaw
What separates the two bones?
Fibrocartilage disk- creates two synovial cavities
Why is the articular disk needed?
The bones are poorly aligned so the disk allows them to fit together.
Describe the capsule surrounding the TMJ
Thin and loose- allows movement but sacrifices stability
Name the 2 ligaments around the TMJ
Temporomandibular ligament x2
Medial ligament x2
Name the 2 accessory ligaments surrounding the TMJ
Sphenomandibular
Stylomandibular
What is the function of the sphenomandibular ligament?
Prevents inferior dislocation of the jaw
Why is dental hygiene important for the stability of the TMJ?
The jaw becomes much more stable when the jaw is closed
Which structure limits posterior dislocation?
The posterior glenoid tubercles
Which structure limits anterior dislocation?
Articular tubercle
What movement does the superior cavity produce?
Translation of the mandible
What movement does the inferior cavity produce?
Rotation of the mandible
Describe the process of closing the mouth
Posterior fibres of temporalis pull mandible backwards
Temporalis, masseter and medial pterygoid elevate the mandible
Describe the process of opening the mouth
Condyles pulled forward by lateral pterygoids
Chin pulled down and back by digastric muscles in lower cavity
What is bruxism?
Grinding of the teeth at night
Where is the infratemporal fossa located?
Below middle cranial fossa
Deep to zygomatic arch
Behind maxilla
Describe the borders of the infratemporal fossa
Anterior: Posterior surface of maxilla Posterior: carotid sheath Lateral: ramus of mandible Medial: Lateral pterygoid plate of the sphenoid Floor: Medial pterygoid muscle Roof: Greater wing of sphenoid
Name the 3 muscles which lie in the infratemporal fossa
Lower part of temporalis
Lower part of medial pterygoid
Lower part of lateral pterygoid
Which nerves lie in the infratemporal fossa?
Mandibular nerve
Chorda tympani
Otic ganglion
Which artery lies in the infratemporal fossa?
Maxillary artery which becomes the middle meningeal artery
Which artery lies superficially to the infratemporal fossa?
Superficial temporal artery
Which veins pass through the infratemporal fossa?
Pterygoid venous plexus
Maxillary vein
Middle meningeal vein
Name the 5 openings of the infratemporal fossa
Foramen ovale Foramen spinosum Alveloar canal Inferior orbital fissure Pterygomaxillary fissure
Why is the infratemporal fossa a potentially dangerous place to grow a tumour?
Tumour can grow relatively large without being detected as it fills the potential space.
Will present late with numbing of the teeth and lips
