TMJ Flashcards
What type of joint is the TMJ?
Bilateral synovial joint
What surfaces articulate in the TMJ?
Mandibular condyle and glenoid fossa
What does the TMJ play an essential role in?
Speaking and eating
What is the mandibular glenoid fossa?
- Depression in the temporal bone in which the mandibular condyle sits in to form the TMJ.
What is the articular eminence of the temporal bone?
Gentle slope of bone covered in cartilage.
What type of bone is the Condyle?
Dense cortical bone covered in dense fibrous connective tissue.
What are the bony landmarks of the TMJ?
Mandibular glenoid fossa
Articular eminence of temporal bone
Mandibular condyle
What 3 ligaments give passive stability to the TMJ?
Temporomandibular lateral ligament
Stylomandibular ligament
Sphenomandibular ligament
Non bony components of the TMJ?
Articular capsule
Synovial tissue
Articular disc
Ligaments
What is the articular capsule?
Fibrous membrane surrounding the joint and attaches to; articular eminence, articular disc and neck of mandibular condyle
What is the articular disc?
Fibrous extension of the capsule that runs between and articulates with the glenoid fossa and mandibular condyle
What shape is the articular disc?
Biconcave disc shape; the condyle sits in the depression
What are the functions of the ligaments involved with the TMJ?
Temporomandibular ligament limits extreme wide opening and lateral movements
Accessory ligaments limit border movements of mandible
Where does the stylomandibular ligament run to and from?
Styloid process to angle of mandible
Where does the sphenomandiblar ligament run to and from?
Spine of sphenoid bone to lingula of mandible.
Where is the temporomandibular ligament located and what are the 2 parts?
Thickened lateral portion of capsule
Outer oblique and inner horizontal
In which ways can the mandible move?
Depression and elevation
Lateral deviations
Protrusion and retrusion
What are the 3 axis of rotation in the TMJ?
Horizontal
Frontal
Sagittal
Which axis is used when the mandible moves up and down?
Horizontal
What axis’ are involved in lateral movements of the mandible?
Frontal
Sagittal
What happens during the first 20mm of jaw opening?
Mandible rotates on horizontal axis whilst the articular disc stays in place
What happens if jaw opening exceeds 20mm?
The articular disc elongates and slides forward. The condyle is then able to glide over the articulating eminence to allow for full opening.
What is the most common form of TMD?
Myofascial pain - discomfort/pain in muscles that control jaw function as well as neck and shoulder.
What is degenerative joint disease in the TMJ?
Osteoarthritis or rheumatoid arthritis
