Temporomandibular Joints Flashcards
What is the glenoid fossa
Base of skull
Where head of condyle articulates the temporal bone
What is the anterior margin of the TMJ
Articular tubercle which prevents TMJ dislocating Anteriorly
What is a typical joint
2 bones lined with hyaline cartilage
Articular surfaces lined with hyaline cartilage
Non-articular surface lined with synovial mem which nourishes , reduces friction, cools the joint, remove waste
Has a capsule to enclose the joint and retain fluid
Ligaments to strengthen the joint
Skeletal ,us les move joint
What is a unique synovial joint
TMJ
Articular surfaces all fibrous tissue
Temporal bone covered in periosteum
Intra articular disc made of dense fibrous tissue
Head of mandibular condyle covered in perichondrium
What is the lingula
At opening of mandibular foramen
Passing down through foramen is the inferior alveolar nerve form Vc
Links formed by powerful ligament attachment of sphenomandibular ligament
What is the retro molar triangle
Area of bone depression
After 3rd molar
Imp for pterygomandibular raphe
What su the pterygoid fovea
Lateral pterygoid muscle attachment
Muscle of mastication
What is the transverse crest of the condyle head
Angulation dividing condylar head into posterior and anterior condylar facets
What is the head of the condyle like
Tilted Anteriorly
Flattened A-P
Elongated latero-medially
Long axis points Posteriorly
What does the lateral temporomansibular ligament do
Prevent dislocation Posteriorly
What does the joint capsule do
Attaches around circumferences of articular surfaces
What are the attachment points of stylomandibulad ligament
Styloid process to medial aspect of angle of mandible
What is the stylomandibulad ligament a specialisation of
Deep cervical fascia - investing layer
What is the sphenomandibular ligament
Remains meckels cartilage
From spine of sphenoid to lingula on mandible
What are the attachments of the pterygomandibular raphe
Pterygoid hamulus to retro molar triangle ( Buccinator origin)
What does the intra articular disc do with the joint capsule
Merge with joint capsule around its circumference ensuring separation of joint into 2 discrete spaces upper and lower spaces
What does the intra articular disc do for movement of TMJ
Provides stability of joint during movement by improving ‘fit’ between the bony articulating surfaces
What is the intra articular disc made up of
Dense fibrous connective tissue
How many zones are associated in he intra articular disc
5 zones
What is the anterior extension of the intra articular disc
Continuous with joint capsule Anteriorly and with tendon of lateral pterygoid muscle
What is the posterior extension of the intr articular disc
Bilaminar
Upper layer - elastic fibres assist disc returning to rest
Both layers - vascular tissue which engirge with blood on opening and empties into pterygoid venous plexus on closing
What are the final 3 layers of the intra articular disc
3 bands in disc proper
Anterior thick
Intermediate thin
Posterior thick
What are the two joint cavities
Upper and lower joint spaces formed by intra articular spaces
What happens in initial opening for the TMJ
Anterior rotation of head of condyle
Movement occurs in lower joint space
Disc remains in place
