TMD - Anatomy Flashcards
What does tempo-mandibular joint comprise of?
Mandible bone
Temporal bone
Tempromandbiular joint an dmuscles
How do mandible and temporal bone interact?
Condyle sits in mandibular fossa in the temporal bone - separated by articular disc
How does condyle move across temporal bone?
Condyle and articular disc translate across articular eminence
Where does temporals muscle attach?
Coronoid process
What muscles attach mastoid process and what help?
Sternocleidomastoid muscle
Digastric muscle
Help open mandible
What surrounds TMD joint?
Fibrous articular capsule - reinforced TMD ligaments
What is articular disc made from?
Fibrous tissue
Special feature of articular disc?
Bioconcave - allows better fit between fossa and condyle
How is articular disc split?
Into upper and lower compartment
What movement happens in lower compartment?
Condyle rotates below the disc - hinge-like motion
What movement happens in upper compartment?
Condyle and disc translate along eminence - disc remain on condyle during movement
Difference between first and second part opening?
First 25mm = rotation of condyle in fossa = hinging
Second half = forward translation of condyle along eminence
What muscle pull chin down and back?
Digastric and geniohyoid
Geniohyoid - pull down
Digastric - pull down and back
What muscles allow forward translation of condyle?
Lateral pterygoid
What muscle pulls condyle back into fossa?
Temporalis
What muscles elevate mandible on closing?
Temporalis, masseter and medial pterygoid
What mm expect of protrusion?
10mm
What expect see protrusion?
Symmetrical forward translation both condyles
What muscle cause protrusion
Lateral pterygoids
What muscles cause retrusion?
Temporalis muscle
How many mm see lateral excursion?
10mm
What happens in lateral excursion?
Condyle on opposite side is pulled forward due contraction lateral pterygoid
Condyle on same side has minimal rotation - temporals contract same side to hold position
