Head and Neck: The Temporomandibular Joint Flashcards
What structures articulate in the TMJ joint?
The condyle of the mandible, the articular tubercle of the temporal bone and the mandibular fossa
What is the articular disk?
A disk of fibrocartilage that divides the joint into a superior and inferior joint cavity. This allows separate movements to occur in each space
What are the 3 ligaments supporting the TMJ joint?
The temporomandibular ligament (covers the actual joint)
The stylomandibular ligament - goes from the styloid process to the mandibular angle
The sphenomandibular ligament - extends from the sphenoid bone to the mandible
(google an image of these)
Which muscles elevate the mandible at the TMJ?
The temporal muscle, masseter and medial pterygoid
Which muscles depress the mandible at the TMJ?
Lateral pterygoid, supra and infra hyoid musckes
However depression is mostly done by gravity
Which muscles protrude the mandible at the TMJ?
Mainly lateral pterygoid
Which muscles retrude the mandible at the TMJ?
Temporal muscle
Which muscles laterally move (chewing) the mandible at the TMJ?
Temporal of the same side, pterygoids of opposite side
Masseter
How does the TMJ become dislocated? ‘eg lock jaw’
If there is a sideways blow to the jaw whilst the mouth is open it can cause an anterior dislocation on the same side. It important to check for a fracture on the opposute side
How can a TMJ dislocation be corrected?
Either manually push the jaw inferior or posterior
Or make a stack of tongue depressors and made the pt bite
What is the infratemporal fossa?
An irregular shaped space deep and inferior to the zygomatic arch and ramus of mandible.
What makes up the borders of the infratemporal fossa?
Superiorly: greater wing of sphenoid Inferiorly: medial pterygoid Laterally: ramus of mandible Medially: lateral pterygoid plate of sphenoid Anteriorly: posterior maxilla Posteriorly: temporal bone
What are the contents of the infratemporal fossa?
3 muscles: Temporal muscle and lat and medial ptergoids
1 artery: maxillary artery
1 plexus: pterygoid venous plecus which communicates with the cavernous sinus
Nerves: mandibular, inferior alveolar, lingual, buccal, chorda tympani, otic ganglion
What is the clinical importance of the infratemporal fossa?
- Can be used as a site of mandibular nerve blocks (dentists)
- If there is an infection it can cause cavernous sinus thrombosis
- can be a site for isolated infections in diabetics, sometimes meningiomas
