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TMJ Temporomandibular Joint
The temporomandibular joint (TMJ) connects the mandible to the temporal bone and allows for mastication and speech. It is a synovial joint with an articular disc that divides it into upper and lower compartments. The disc is attached to the fibrous capsule and provides cushioning between the articulating surfaces of the temporal bone and mandible. The TMJ has ligaments that reinforce the joint and is supplied by nerves from the mandibular nerve. It allows for important movements of the mandible like depression, elevation, protrusion, and retrusion.
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TMJ Temporomandibular Joint
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- 2. Introduction • The mostimportant functions of the Temporomandibular joint (TMJ) are:- Mastication and speech
- 3. . • The rightand left TMJ form a bicondylar articulation. • The features that differentiate and make this joint unique are its articular surface covered by fibro cartilage instead of hyaline cartilage.
- 4. Peculiarity of TMJ •Bilateral diarthrosis – right & left function together 1. Articular surface covered by fibrocartilage • instead of hyaline cartilage
- 5. Type of joint •Synovial joint • Condylar variety
- 6. components • Articular surfacesof Temporal bone • Articular disc • Mandibular condyle Ligaments
- 7. Articular surface • Upperarticulating surface (temporal bone) • Lower articulating surface (head of the mandible) • The articular surface are covered by FIBROCARTILAGE • In between the upper and lower articulating surface is an Intra articulating disc
- 8. Upper articulating surface •Formed by the following parts of the Temporal bone 1. Articular tubercle 2. Anterior part of the mandibular fossa 3. Posterior non articulating part formed by the tympanic plate
- 9. Lower articulating surface •Formed by the head of the mandible
- 10. LIGAMENTS 1. Fibrous capsule 2.The Lateral ligament 3. The Sphenomandibular ligament 4. The Stylomandibular ligament
- 11. 1. Fibrous capsule •It is attached above to :- 1. The Articular tubercle 2. The circumference of the mandibular fossa (in front) 3. The squamotympanic fissure (behind) • It is attached below to :- 1. The neck of the mandible • The capsule is :- -- LOOSE above the intra articular disc -- TIGHT below the intra articular disc • The synovial membrane lines the fibrous capsule and the neck of the mandible
- 13. 2. The lateralTemporomandibular ligament • It reinforces and strengthens the lateral part of the capsular ligament • It’s fibres are directed downwards and backwards • Its attached - Above – to the Articular tubercle - Below – to the posterolateral aspect of the neck of the mandible
- 15. 3. The Sphenomandibularligament • It is an Accessory ligament • Lies on the deep plane away from the fibrous capsule • It is attached:- - Above – to the spine of sphenoid - Below – to the lingula (mandibular foramen)
- 16. . • This ligamentis related Laterally to the:- 1. Lateral Pterygoid muscle 2. Auriculotemporal nerve 3. Maxillary artery • This ligament is related Medially to the:- 1. Chorda tympani nerve 2. Wall of the pharynx
- 18. 4. The Stylomandibularligament • It is an Accessory ligament • It represents the thickened part of the Deep Cervical Fascia (deep lamina) • It separates the parotid gland from the submandibular gland • Attached :- - Above – to the styloid process - Below – to the angle & post. border of ramus of mandible
- 20. ARTICULAR DISC • Isan oval FIBROUS PLATE • Present in between the upper and lower articulating surface • Divides the joint cavity into upper and lower compartments • Upper compartment – permits GLIDING MOVEMENT • Lower compartment – permits ROTATORY as well as GLIDING movements
- 21. . • The disc -superior surface = concavo-convex - inferior surface = concave • The periphery of the disc is attached to the fibrous capsule. • The DISC is composed of :- 1. Anterior extension 2. Anterior thick band 3. Intermediate zone 4. Posterior thick band 5. Bilaminar region ( containing venous plexus)
- 23. Function of thearticular disc • It prevents friction between 2 articulating surface • Provides cushion like consistency • Prevents from shock • Fills the gap and helps in distribution of the weight across the TMJ • The proprioceptive fibres present in the disc help to regulate movements of the joint
- 24. Relations of TMJ LATERAL 1.Skin and fascia 2. Parotid gland 3. Temporal branch of facial nerve Medial 1. The tympanic plate 2. Spine of sphenoid (with upper end of spine of sphenoid) 3. Auriculotemporal and chorda tympani nerves 4. Middle meningeal artery
- 25. ANTERIOR 1. Lateral Pterygoid 2.Masseteric nerve and artery POSTERIOR 1. Parotid gland (separates the TMJ from external acoustic meatus) 2. Auriculotemporal nerves SUPERIOR 1. Middle cranial fossa 2. Middle Meningeal vessels INFERIORLY 1. Maxillary artery and vein
- 26. . BLOOD SUPPLY /venous drainage • Branches from :- - Superficial temporal & maxillary artery • Veins follows the artery NERVE SUPPLY • Masseteric nerve (from the main trunk of mandibular) • Auriculotemporal nerve (post trunk of mandibular)
- 27. Movements 1. Depression (openingof mandible) 2. Elevation (closing) 3. Protrusion 4. Retrusion 5. Lateral / side to side movement