Temporomandibular Joint Flashcards
What type of joint is the TMJ?
Synovial hinge joint which is separated into two synovial cavities by a fibrocartilagneous disc
What are conditions affecting the TMJ?
TMJ disordering- pain( refers to ear, jaw, lateral side of head, clicking and locking
TMJ dislocation- secondary to traum/ yawning
Arthritis
What nerve is the TMJ innervated by?
Auriculotemporal nerve
What is the auriculotemporal nerve?
Branch of mandibular division of the trigeminal nerve
What are ten articular surfaces of the TMJ lined with?
Fibrocartilage they do not come into direct contact
How does the initial opening of the jaw occur?
Hinge rotational action in the inferior half of the joint cavity
How do you open your jaw more widely?
Condyle glides over the articular tubercle and occurs in superior half of joint cavity
What are the actions of the mandible?
Elevation Depression Protrusion Retraction Grinding
What muscles are used in the elevation of the jaw?
Masseter
Temporalis
Medial pterygoid
What muscles are used in depression of the mandible?
Lateral
Also uses gravity
Against resistance uses the platysma and suprahyoids
What muscles are used for protrusion or protraction?
Lateral
Medial pterygoid assists
What muscles are used in retraction?
Posterior fibres of temporalis
What muscles are used in the grinding of the jaw?
Muscles of both sides working cooperatively
What happens in the dislocation of The TMJ?
Jaw locks in a n open position due to anteriorncondyle moving over articular tubercle
