A23 - Tempomandibular Joint Flashcards
what are the properties of a typical synovial joint?
- articular surfaces are lined by hyaline cartilage
- non-articular surfaces lines with synovial membrane
- capsule to enclose and retain fluid
- ligaments to strengthen joint
- skeletal muscles to move joint
What is the importance of the synovial membrane?
- contains fluid to nourish the articular surfaces
What does the synovial fluid do?
- reduces friction
- to cool the joint
- to remove waste products
What is the difference between the TMJ joint?
- all articular surfaces are FIBROUS
- temporal bone is covered in periosteum
- infra-articular disc is made of dense fibrous tissue
- head of mandibular condyle in perichondrium
- infra-articular disc is split into superior and inferior synovial cavities with their own synovial membrane
what makes up the TMJ?
- base of the temporal bone
- glenoid fossa of temporal bone
- head of the mandibular condyle
what is the function of the articular tubercle and where is it situated?
anterior to the glenoid fossa and prevents anterior dislocation
what is posterior to the glenoid fossa?
post-glenoid tubercle which prevents posterior disslocation
why is the post -glenoid tubercle less pronounced?
there are ligaments which also prevent dislocation
what is the function of the ptyergoid fovea?
where the lateral ptyergoid attaches and the disc is structurally connected to the ligament of this muscle
what is the key features of the condyle head?
- elongated latero-medially
- tilted anteriorly which helps it optimally articulate with the glenoid fossa
what is the joint capsule?
bandage that wraps around the joint to keep it complete, aiding stabilisation and keeps the synovial fluid in the joint
what ligament prevents posterior dislocation?
lateral temporomandibular ligament
what is the structure and function of the stylomandibular ligament?
- connects from the styloid process to the medial aspect of the angle of the mandible
- specialisation of the investing layer of deep cervical fascia surrounding the parotid gland
- weak ligament and restricts jaw openong
what is the importance and structure of the sphenomandibular ligament ?
- arises in the spine of the sphenoid and attached to the lingual
- main action is to prevent excessive jaw opening
what is the structure and function of the pterygomandibular raphe?
- extends from the hamulus of the pteygoid plate of the sphenoid down towards the retro-molar space
- role in attachment of other soft tissue including the buccinator muscle