Tmj Flashcards
Secondary curves?
Cervical, lumbar
Anterior convexity
Primary curves?
Thoracic, sacral
Posterior convexity
What do the condyles of the mandible sit in?
Mandibular Fossa
Post glenoid tubercle (posteriorly)
Articular eminence (Anteriorly)
type of joint tmj?
Snyovial
Proximal/stationary part of tmj
Temporal bone
Primary articular surface of mandibular condyle?
Articular eminence
Kind of cartilage Articular eminence has?
Fibrocartilage
Can repair and remodel
High forces when biting
Incongruent joint?
Articular eminence (convex) Mandible condyles (convex)
Inferior tmj joint ?
Type of joint ?
1st joint
Mandibular condyle + inferior surface disc
Hinge joint
Superior tmj joint
2nd joint
Articular eminence + superior surface disc
What is the disc attached to?
Medial/ lateral poles of condyles
Allow Condyle to rotate freely on disc in anterior/posterior direction
Disc attached to anteriorly?
What do they restrict?
Joint capsule
Lateral pterygoid muscle
Restrict posterior translation of disc
What is the disc attached to Posteriorly?
Bilaminar retrodiscal pad
Superior/inferior lamina
Superior lamina of bilaminar retrodiscal pad allows?
Disc to translate anteriorly (opening)
Assist with closing
Inferior lamina of bilaminar retrodiscal pad limits?
Anterior translation
If someone dislocates their jaw anteriroly what would be stretched?
Inferior lamina
Function of Articular disc? (5)
Increase stability Min loss of mobility Reduces friction Decreases street Collage, glyco, elastin= cannot repair/remodel
Where is the capsule loose?
Anterior (mostly)
medial
Posteriorly
Where is the capsule strong ?
Laterally
TMJ ligament limits?
Downward/ posterior motion of mandible
Rotation during mandibular depression
Lateral displacement
What does the stylomandibular lig limit?
Protrusion
Osteokinamatics of tmj
Depression Elevation Protrusion Retrusion Lateral excursion
ROM for depression
40-50 mm
What happens in depression?
Anterior roll (condyle/inferior disc) Anterior glide (superior disc/ Articular eminence)
What happens in elevation ?
Posterior roll (condyle/inferior disc) Posterior glide (superior disc/ Articular eminence)
What controls the disc and attaches anteriorly during elevation ?
Lateral pterygoid
Eccentric control
What limits protrusion?
Superior lamina of retrodiscal tissue
Protrusion is important for?
Opening/depression
Protrusion/Retrusion occur?
In the upper tm joint
Retrusion is important for?
Closing your mouth
What is retrusion limited by?
Temporomandibular ligament
Compression of retrodiscal area
ROM for lateral excursion?
8-11 mm
Lateral excursion arthro?
Ipsilateral condyle = spin in transverse plane in Fossa
Contralateral condyle = translates anteriorly along anterior eminence
Deviation?
S curve
Mandible moves away from midline then back
Deflection?
C curve
Mandible moves away from midline doesnt come back
Primary muscles of tmj?
Temporalis
Masseter
Lateral pterygoid
Medial pterygoid
Temporalis?
Closing, retrusion
Ipsilateral deviation
Masseter?
Closing/retrusion
Lateral pterygoid?
Protrusion
Contralateral deviation
Eccentric control disc upon closing
Medial pterygoid ?
Closing
Protrusion
Contralateral deviation
Secondary muscle?
Suprahyoid (mandibular depression)
Infrahyoid (stabalize hyoid)
Resting posture of tmj
1.5-5 mm open
