Temporomandibular joint Flashcards
What type of joint is it?
Synovial
What type of cartilage coats the bone surfaces?
Fibrocartilage which can grow and repair (a type of articular cartilage)
What is the function of the articular disc?
Pressure absorbing device and splits joint into 2 compartments allowing 2 types of movement
What surrounds the joint and attaches the bones?
Capsule ligament
Between which bones does the joint form?
Mandibular condyle and temporal bone (mandibular fossa)
What are the attachments of the capsule?
Mandibular fossa and articular eminence of the temporal bone superiorly.
To the neck of the condyle
What is the temporomandibular ligament?
Lateral thickening of the capsule
What are the attachments of the sphenomandibular ligament?
Spine fo. sphenoid to mandibular fo.
What is the function for the sphenomandibular ligament.
Hinge movement meaning no rotation at the point the inferior alveolar nerved artery run
What provides sensory innervation to the joint?
Branches of the auriculotemporal nerve, small anterior portion supplied by temporal branches of V3
Why are there free nerve endings?
Send pain impulses to limit excessive movements of the mandible
What provides the blood supply to the joint?
Branches from superficial temporal artery. Small anterior portion supplied by branches of maxillary artery
What are the 2 types of movement about the joint?
Hinge and translation
Where does the movement occur during the hinge movement?
Between condyle and disc = lower compartment
What ligament is used during hinge movements?
Sphenomandibular ligament
What moves during a hinge movement?
Condyle moves, disc stays stationary
Where is the axis of rotation for hinge movements?
Mandibular fo.
Where does the movement occur during a translatory movement?
Between disc and mandibular fossa (upper compartment)
What moves during translation movement?
Condyle and disc move together
What muscles move the jaw?
Supramandibular - muscles of mastication - massater, temporali, medial pterygoid, lateral pterygoid.
Inframandibular - supra hyoid and infra hyoid
What muscles are used to open the jaw?
Inferior head of lateral pterygoid causes protraction.
Anterior digastric shortly after. Then gravity takes over.
Further opening first uses supra hyoids and platysma, then infra hyoids
What muscles are used to close the jaw?
Massater, medial pterygoid and when closing against resistance uses temporals.
Superior head of lateral pterygoid then places condyle back into mandibular fossa
At rest the jaw is held with teeth about 5mm apart, how is this maintained?
Using the muscles that close the jaw
