What is the temporomandibular joint?
A modified synovial joint between the cranium and the mandible
What are the articulations of the temporomandibular joint?
- Condyle of the mandible
- Articular tubercle of temporal bone
- Mandibular fossa
What does the articular disc of the TMJ do?
Divides the TMJ into superior and inferior compartments
Describe the joint capsule of the TMJ?
What is the result of the joint capsule of the TMJ being relatively loose?
It sacrifices stability for movement
What ligaments support the TMJ?
- Lateral ligament
- Stylomandibular ligament
- Sphenomandibular ligament
What is the most important of the TMJ ligaments?
What is the lateral ligament of the TMJ also known as?
The temporomandibular ligament
Where is the lateral ligament of the TMJ?
Between the temporal bone and the mandible
Where does the stylomandibular ligament run?
From styloid process to behind angle of mandible
Where does the sphenomandibular ligament run?
Sphenoid bone to internal surface of mandible
What muscles are responsible for elevation of the TMJ?
- Anterior fibres of temporal
- Medial pterygoid
What muscles are responsible for depression of the mandible?
- Lateral pterygoid
What is depression of the mandible mostly done by?
When are muscles required for depression of the mandible?
When against resistance
What muscle is responsible for protrusion of the mandible?
Mainly lateral pterygoid
What muscle is responsible for retrusion of the mandible?
Posterior fibres of temporal
What muscles are responsbile for lateral movements of the mandible?
- Temporal on same side
- Pterygoids of the opposite side
What are the muscles of mastication?
What are the muscles of mastication supplied by?
Mandibular branch of trigeminal nerve
What causes a TMJ dislocation?
Commonly a sideways blow to the chin when the mouth is open, whcih causes an anterior dislocation of the same side
What happens in a TMJ dislocation?
Head of mandible moves anteriorly to the articular tubercle
What needs to be checked for when someone presents with a TMJ dislocation?
Fracture on the opposite side of the jaw
How is a TMJ dislocation managed?
Inferior and posterior traction to relocate
Where is pain around the TMJ felt?
Just anterior to the tragus
What nerve supplies the TMJ?
The auriciulotemporal nerve, a branch of TMJ
What must a doctor be aware of as a differential diagnosis when a patient presents with pain around the TMJ?
What is the risk of missing a diagnosis of temporal arteritis?
Loosing patients sight
What can cause pain around the TMJ?
- Bruxism (teeth grinding)
- Osteoarthritis of the TMJ
- Inter-articular disc derangement
What is the likely route of management when there is inter-articular disc derangement?
Surgery to get the abnormality fixed
What % of cases of pain around the TMJ are multifactoral?
What factors contribute to a condition causing pain around the TMJ?
What psychological factors contribute to a condition causing pain around the TMJ?
What social factors contribute to a condition causing pain around the TMJ?