The tempomandibular joint is an articulation between what 2 osseous structures?
The mandibular fossa and the articular tubercle of the temporal bone
The mandibular portions of the TMJ are con____ and the articular eminence of the temporal bone is con____.
convex
concave
The TMJ is what kind of joint?
a modified hinge joint
What movements occur at the TMJ?
Gliding (protrusion/retrusion)
Rotation (grinding and chewing)
Angling (elevation/depression)
What separates the 2 bones of the TM joint?
An oval-shaped fibrocartilaginous articular disc called the articular disc of the TMJ
The articular disc of the TMJ creates what?
2 joint spaces (superior and inferior)
Describe the shape of the articular disc
The central, intermediate portion of the disc is thin while the anterior and posterior aspects, or bands, are thicker
What muscles is attached to the disc anteriorly?
lateral pterygoid
The TMJ allows the mouth to open how wide?
35-40mm or 2 to 3 knuckles
What are the 4 muscles of mastication that move the mandible?
- Masseter
- Temporalis
- Medial Pterygoid
- Lateral Pterygoid
What is the first motion at the TMJ when the mouth opens?
During the first 20 mm the motion is rotation
Describe what the mandible and articular disc do during the first 20 mm of movement
The mandible and meniscus move anteriorly together beneath the articular eminence
What is the second motion at the TMJ when the mouth opens?
During the second 20 mm the motion is translation (the jaw further forward or from side to side)
What are the symptoms of a frayed or dislocated articular disc?
Bitemporal headaches (temporalis muscle overuse), clicking during jaw opening and reduced range of motion
How is a frayed articular disc repaired?
surgically
Temporomandibular Disorders (TMDs) affect more than __% of the population
25%
What percent of those seeking treatment are women?
90%
