9. temporomandibular joint (TMJ) Flashcards
what is the TMJ?
modified hinge synovial joint between cranium and mandible
what is the articulation of the TMJ?
condyle of mandible
articular tubercle of temporal bone
mandibular fossa (temporal bone)
what divides the TMJ into 2 compartments?
articular disk
into superior and inferior compartments
how is the TMJ like as a joint?
relatively loose joint capsule
movement > stability
what is the TMJ joint support by?
3 ligaments:
lateral ligament (temporomandibular ligament)
stylomandibular ligament
sphenomandibular ligament
which muscles carry out the elevation movement of the mandible?
temporal, masseter, medial pterygoid
shutting mouth
which muscles carry out depression of the mandible?
usually gravity
against force: lateral pterygoid, supra/infrahyoid
which muscles carry out protrusion of the mandible?
(jaw sticks out)
lateral pterygoid
which muscles carry out retrusion of the mandible?
temporal muscle
which muscles carry out lateral movements of the mandible? (e.g. chewing)
temporal on same side
pterygoids of opposite side
masseter
which nerve innervates muscles of mastication?
mandibular branch of trigeminal (V3) supplies:
temporalis, masseter, pterygoids
how does TMJ dislocation commonly occur?
a sideways blow to the chin when the mouth is open
what does TMJ dislocation cause?
anterior dislocation of the same side
head of mandible moves anterior to articular tubercle
what should you also check for in a TMJ dislocation?
fracture on the opposite side of jaw
what is the innervation to TMJ?
auriculotemporal nerve (branch of V3)
