L2 - Neuromuscular Determinant Flashcards
(50 cards)
Two bones of the TMJ
Mandibular condyle Temporal bone (squamous part)
+ articular disc
description of mandibular condyle
general parts /shape
top of mandibular neck articulates with glenoid (mandibular fossa) convex elliptical shape medial and lateral poles
Temporal bone - which part and describe shape - what it determines
SQUAMOUS portion
articular eminence
- steepness and condylar guidance
roof of glenoid?
THIN - glenoid fossa is thin at top
TMJ does what movement?
HINGE and GLIDING
ginglymoarthrodial joint
2 types of joint movement occur
Gingylmoid = hinge Gliding = arthrodial = plane joint
Rotate? motion and where?
HINGING movement in the LOWER compartment
Translate? motion and where?
GLIDING movement in the upper compartment
ginglymoarthrodial joint
TMJ synovial type
two types of movement
rotating at hinge - ginglymoid
gliding at arthroidal
TMJ articular surfaces and implication
Fibrocartilage tissue
* fibrocartilage can withstand force of movements and it has a great ability to repair itself (as opposed to hyaline cartilage that does not)
LESS susceptible to the effects of aging and less likely to breakdown overtime
two differences in TMJ vs other synovial joints
TMJ does two movements and articular surfaces are covered by fibrocartilage
anatomy of the articular disc
biconcave fibrocartilaginous structure
flexible and can adapt to the functional demands
what does articular disc prevent?
prevents direct articulation of the condyle and temporal bone
the articulating surfaces of the two bone are incompatible so disc prevents from damage
anterior prominence of condyle where?
CENTRAL THIN PART OF THE DISC
posterior border of the articular disc?
at a 12 o’clock position on the condyle
function of synovial fluid
lubrication and nutrition
boundary lubrication vs weeping lubrication
boundary - lubrication continues - goes in and out of articular surfaces
weeping = lubrication when we keep closed
general characteristics of the ligaments of the TMJ
- fibrous connective tissue that connects two bones
- no active participation in the TMJ function
- passive restraining
- do not stretch
- extensive forces may cause elongation which will compromise the joint function
*ONLY restrict the excessive functions
capsular ligament superior? inferior? posterior? function?
superior? = attach temporal bone along the border of glenoid fossa and articular eminence
inferior?= attach to condyle
posterior?= postglenoid process
encompass the TMJ
function? –> retain synovial fluid inside
RESISTS any medial, lateral, or inferior forces that tends to dislocate the articular surfaces
Temporomandibular (lateral) ligament
location and function of outer oblique?
Outer oblique = is attached to the articular tubercule, and runs posterioinferiorly to the outer surface of the condylar neck
*LIMITS rotational opening (20-25 mm) and protects retromandibular structures
Temporomandibular (lateral) ligament
location and function of inner horizontal?
it is attached to the articular tubercle, runs anteriorposteriorly to attach to the lateral pole of the condyle and posterior part of the disc
FUNCTION: limits posterior movement of condyle and disc to protect the retrodiscal tissue
Under extreme force? : condylar neck fractures to prevent the condyle from entering the middle cranial fossa?
collateral (discal) ligaments
Attach?
Function?
Attach medial edge of the disc to the medial pole of the condyle and lateral edge of the disc to the lateral pole and lateral edge of the disc to the lateral pole
Function: allows disc to move passively with the condyle as it glides
Divides joint into superior and inferior cavities
Sphenomandibular ligament
attach and action
Spine of the sphenoid bone, runs downward and outward to lingula of the mandible
NO influence on mandibular movement
Stylomandibular ligament
attach
function
Styloid process to the angle and posterior border of the mandibular ramus
Limits excessive mandibular protrusive movement
