Flashcards in TMJ Deck (30):
What are the fibrous joints?
*Very little movement*
-Sutures - Skull
-Tooth socket - Gomphosis
-Syndesmosis - Immovable CT holding bones together (tibia and fibula)
What are cartilaginous joints?
-Primary (Synchondroses) - Bone and cartilage in direct apposition (Sternocostal junction)
-Secondary (Symphyses) - Fibrous tissue internally in the joint
What are synovial jts?
Capsule filled with synovial fluid contained w/in a synovial membrane
T/F - The TMJ is a synovial jt.
What is the TMJ specifically?
Synovial sliding-ginglymoid joint
General structure of the TMJ?
—Able to rotate and translate in various ways
The TMJ synovial capsule is bound to what 2 things?
*Articular disc separates the 2
What is the extension of the articular capsule?
Origins of the mandible?
Intramembranous ossification, except for ramus, and associated with Meckel’s cartilage
What forms the primary joint?
Meckel’s cartilage forms the malleus and articulates with the incus
This is how a fetus opens it’s mouth
*This is prior to the development of the condyle and temporal bone
What is the secondary joint?
Articulation b/t condylar head and glenoid fossa
T/F - The TMJ articular surfaces are covered with fibrous CT, NOT hyaline.
-It’s a dense fibrous coating.
-Why is this an issue?
What is the dense fibrous tissue on the condyle?
Tell me about the lamina splendens.
Avascular type I collagen w/ fibroblasts
Look at picture on slide 10.
What are the 4 mm of mastication?
T/F - The jt capsule is a dense collagneous sac.
What do the ligaments associated with the TMJ do?
Stabilizes the jt
What are the 3 ligaments to know about the TMJ?
TMJ ligament - Thickened regions that branch out
Sphenomandibular - Connects sphenoid to mandible
Stylomandibular - Connects styloid process to mandible
T/F - Articular disk is continuous with the jt capsule.
What is the articular disc?
Dense fibrous structure
-Collagen fiber network overlaying fibroblast cells
T/F - Posteriorly and anteriorly, the disc is thicker, and the condyle rests on the thinner middle section when jaw is closed
What are the 2 layers of the synovial membrane?
What is the subintima?
-Elastin and vasculature
What is the intima?
Innermost layer with cells
What are the cells of the intima?
—Resemble FIBROBLASTS and contribute PROTEINS in synovial fluid
What is the synovial fluid?
Basically blood plasma, containing extra proteins and proteoglycans
Tell me about the layers of cartilage.
Progenitor cells->chondroblasts (in a proliferative layer) these secrete ECM w/ type II collagen around themselves
->Once entombed, they form hypertrophic chondrocytes
—THESE UNDERGO ENDOCHONDRAL OSSIFICATION
T/F - Mandible is formed by intramembranous ossification, but it is fair to say the articular part of the TMJ is formed by endochondral ossification also.