Mandibular Movements Flashcards
Name the muscles of mastication.
masseter, medial pterygoid, lateral pterygoid, temporalis
What is the action of the masseter muscle?
elevate the mandible
What is the action of the temporalis muscle?
elevate (anterior fibers) and retrude (posterior) mandible
What structure is found behind the articular disc of the TMJ?
retrodiscal tissue
What is the action of the lateral pterygoid muscle?
protrudes, depresses the mandible (superior head) lateral excursion (inferior head)f the mandible unilaterally
What is the action of the medial pterygoid muscle
elevate mandible, protrude mandible, lateral excursion
What is the purpose of the fibrous capsule surrounding the TMJ?
limit mandibular movement
What two movements does the mandible make?
rotational/rotatory and translational/translator (bodily movement)
Name the two terms that refer to the axis that connects the condyles and they rotate/translate around.
terminal hinge axis
transverse horizontal axis
both called THA
When the mandible moves laterally which condyle (working or nonworking) moves within the cone of Bennett?
working condyle
When the mandible moves laterally, which condyle moves down, forward and medial?
non-working condyle
What distance is the rotational movement limited to before the mandible begins to translate?
12.5 mm (some say 20-25 mm, this may be too far)
What is Bennett’s movement?
lateral translation
Describe the chewing movement.
open, lateral motion, then closed
What is the arc of rotation?
arch formed by the limited opening involving only rotation of the mandible around THA
