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Presentation on theme: "TMJ."— Presentation transcript:


2 TMJ?


4 The only joint in the head?

5 No

6 Type of the joint?

7 Synovial

8 Bone Muscle Ligaments Innervation Function

9 LEARNING OBJECTIVE Describe the anatomical structures of the joint
Explain the articulating surfaces of the bones Describe the embryology of the joint Identify: capsule, synovial membrane, ligament and articulating disc Describe the muscles and the movements that take place in the joint Describe the nerve and blood supply to the joint Explain how dislocation of the joint can occur

10 TMJ Joint/ articulation?
Connection between two separate parts of skeleton Mandible and the two temporal bones Craniomandibular joint Bilateral articulation the only visible movable joint in the head

11 Exercise Palpate the TMJ

12 Three articulating parts:
Articular eminence (or tubercle) Articular fossae Mandibular condyle Enclosed by fibrous connective tissue capsule



15 Mandibular condyle Surface covered by thickened layer of fibrous connective tissue


17 Articular fossa and articular eminence
Articular fossa – non functioning portion Articular eminence functioning portion Just anterior to the articular fossa Lined by thicker layer of fibrous tissue


19 Articular disc Tough oval pad of dense ficrous connective tissue
Surface – smooth Thinner in the centre than around the edges Concave anteriorly to fit under the articular eminence Convex posteriorly to conform to the shape of articular fossa Flattened disc  problems

20 Articular disc Function:
Partitioning the complex condylar movement into upper and lower functional components Lubricating with synovial fluid Stabilising condyle Cushioning the loading Reducing physical wear and strains Helping regulate movements of the condyle


22 How does TMJ differ from other synovial joints?
TMJ develops between 8 – 14 weeks compared to 5-8 weeks for other synovial joints TMJ – initially widely separated temporal and condylar blastema that grow towards each other Limb joint develops to adulthood by cavity fromation within single blastema Fibrous cartilagerather than hyaline cartilage

23 Embryology 10 – 12 weeks pc Ossification of the temporal components begins independently of the events in the mandible the condylar cartilage is present at the most superior aspect of the ramus. the embryonic connective tissue (mesenchyme) between the growing condyle and temporal bone condenses to form the articular disc Inferior compartment form first (10 weeks) , upper (11.5) cavitation forms the lower joint compartment and then the upper compartment

24 14 weeks Joint development completed

25 Development Infants: During development
Articular fossa, articular eminence and condyle – flat About the same level as occlusal plane Why? During development Articular fossa deepens Articular eminence - > prominent – when? Condyle becomes rounded

26 Accelerates until 12th year of life
Growth Structure grow laterally – widening of the neurocranium Mature disc – changes shape, more compact, less cellular, more collagen Condyle contains cartilage After eruption of permanent dentition, articular tubercle becomes prominent Accelerates until 12th year of life

27 Fibrous capsule Sheet/sac/tube of tissue Encloses the joint
Fairly thin Lateral – temporomandibular ligament Attachment – upper – circumference of articular fossa Lower – neck of the condyle

28 Two layers: Inner layer (synovial membrane) Outer layer
Lines fibrous capsule Covers the bone Secretes synovia – lubricates and nourishes Outer layer Thicker layer of fibrous tissue Accessory ligaments


30 Ligaments Capsular ligament – restricts posterior movement of condyle
Temporomandibular ligament Attachment – upper – zygoma arch, lower – side and back of condyle neck keeps condyle close to the fossa Helps prevent lateral and posterior displacement Stylomandibular ligament Posterior to the joint Attached at the _____ and _____ Sphenomandibular ligament Medial to the joint Limit maximum opening Attached to ______ and _______


32 Articular disc Dense fibrous connective tissue
Between mandibular condyle and articular fossa/eminence Thinner – center Anteriorly and laterally Act as a buffer

33 Muscles Muscles of mastication Masseter Temporalis Medial pterygoid
Lateral pterygoid

34 Masseter Most superficial, powerful Quadrilateral
Origin: Zygomatic arch – inferior and medial surface and temporal process of zygomatic bone Insertion: lateral surface of the ramus Function: closes jaw, crushing

35 Temporalis muscle Fan shaped, large but flat muscle
Origin: entire temporalis fossa (part of frontal and parietal bone, squamous part of temporal and greater wing of sphenoid) Directed downward (anterior), downward, anteriorly (posterior part) – passing medial to zygomatic arch Insertion: coronoid process, anterior border of ramus and temporal crest Action: elevator, retractor

36 Medial pterygoid Medial to ramus
Origin: medial surface of lateral pterygoid plate and pterygoid fossa, pyramidal process of palatine bone Pass downward, laterally towards the angle of mandible Insertion: medial surface of mandible in triangular region Action: elevator

37 Lateral pterygoid Horizontal fibres Short, thick
Located in the infratemporal fossa Prime mover of mandible except closing Origin: 2 heads – upper head – infratemporal surface on great wing of sphenoid Lower head – lateral side of pterygoid plate on sphenoid bone Insertion: upper head – neck of condyle and anteroposterior surface of capsular ligament, into disc Lower head – roughened pterygoid fovea on anterior surface of neck of condyle

38 Action: opening the jaw
Pulling articular disc and condyle forward down onto articular eminence


40 Innervation Proprioceptive neurons in capsule and disc
Trigeminal nerve (cranial nerve V) – auriculotemporal branch of ______ Branches of mandibular division of the TN (auriculotemporal, deep temporal and masseteric) supply the joint

41 Blood supply branches of external carotid artery
Ascending pharyngeal and superficial temporal branches Anterior tympanic Massteric Middle meningeal branch of maxillary artery -


43 Stuck in front of articular eminence
Problem Dislocation Extreme opening of the jaw – laughing, dental treatment Condyle moves too far Stuck in front of articular eminence Muscle spasm



46 Name the bony components of TMJ?
Muscles that close the jaw Nerve innervate the joint

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