Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== TEMPOROMANDIBULAR JOINT ====== Temporomandibular joint * Type * Synovial * Condylar type * Articular surfaces * Upper articular surfaces : * Articular tubercle * Anterior part of mandibular fossa * Posterior non articular part formed by tympanic plate * Inferior articular surface is formed by head of mandible * Coverings * Covered with fibrocartilage * Cavity * Joint cavity divided by intraarticular disc * Upper and * Lower part * Ligaments * Fibrous capsule * Attached * Above to articular tubercle , circumference of mandibular fossa infront and squamotympanic fissure behind * Below * Neck of mandible * Capsule * Loose above intra articular disc and tight below it * Synovial membrane lines the fibrous capsule and neck of mandible * Lateral temporomandibular ligament * Reinforces and strengthens lateral part of capsular ligament * Fibres directed downwards and backwards * Attached * above to articular tubercle * Below to posterolateral aspect of neck of mandible * Sphenomandibular ligament * Accesory ligament * Lies in a deep plane away from fibrous capsule * Attached superiorly to spine of sphenoid * Inferiorly to lingula of mandibular foramen * Remnant of meckels cartilage * Relations. * Medial * Chorda tympani nerve * Wall of pharynx * Lateral * Lateral pterygoid muscle * Auriculotemporal nerve * Maxillary artery * Stylomandibular ligament * Accesory ligament of the joint * Thickened part of deep cervical fascia * Separates parotid and submandibular salivary glands * Attached above to lateral surface of styloid process * Below to angle and adjacent part of posterior border of ramus of mandible * ARTICULAR DISC * oval fibrous plate * Upper compartment * Gliding * Lower compartment * Rotatory and gliding * Surface * Concavo convex superior surface * Concave inferior surface * Attachment * Periphery attached to fibrous capsule * Disc * Anterior extension * Anterior thick band * Intermediate zone * Posterior thick band * Bilaminar region * Represents degenerated primitive insertion of lateral pterygoid * Function * Prevents friction between articulating surface * Acts as a cushion , helps in shock absorption * Stabilises condyle by filling up space between articulating surface * RELATIONS OF TMJ * Lateral * Skin and fascia * Parotid gland * Temporal branches of facial nerve * Medial * Tympanic plate separates the joint from internal carotid artery * Spine of sphenoid with upper end of sphenomandibular ligament * Auriculotemporal and chorda tympani nerves * Middle meningeal artery * Anterior * Lateral pterygoid * Masseteric nerve and artery * Posterior * Parotid gland separates joint from external auditory meatus * Superficial temporal vessels * Auriculotemporal nerve * Superior * Middle cranial fossa * Middle meningeal vessels * Inferior * Maxillary artery * Maxillary vein * BLOOD SUPPLY * NERVE SUPPLY * MOVEMENTS * depression ( open mouth ) * Elevation ( closed mouth ) * Protrusion ( protraction of chin ) * Retrusion ( retraction of chin ) * Lateral or side to side movements ( chewing or grinding ) | Articular surfaces | Temporal bone: Mandibular fossa and articular tubercle | | | | Mandible: Condylar process | | | Main components | Joint capsule | | | Synovial membrane | Synovial membrane | | | | Articular disc (anterior/posterior bands, intermediate zone) | | | Ligaments | Major: Lateral temporomandibular ligament (thickened lateral portion of capsule, strengthens TMJ laterally) | | | | Minor: Stylomandibular ligament, sphenomandibular ligament | | | Cavities | Superior (discotemporal) cavity (translational movement) | | | | Inferior (discomandibular) cavity (rotational movement) | | | Rotational movements | Elevation: Temporalis, masseter and medial pterygoid muscles | | | | Depression: Lateral pterygoid, digastric, geniohyoid and mylohyoid muscles | | | Translational movements | Protrusion: Lateral pterygoid, medial pterygoid muscle, masseter | | | | Retraction: Posterior fibers of temporalis, deep part of masseter | | | | Lateral deviation (left or right): Posterior fibers of temporalis, digastric, mylohyoid and geniohyoid muscles (ipsilateral movement); lateral and medial pterygoid muscles (contralateral movement) | | ===== ARTICULAR SURFACES ===== ===== LIGAMENTS ===== * fibrous capsule * lateral temporomandibular ligament -- articular tubercle --> neck of mandible * Sphenomandibular ligament - spine of sphenoid --> lingula of mandibular foramen * stylomandibular ligament - lateral surface of styloid process ===== MOVEMENTS ===== en/temporomandibular_joint.txt Last modified: 2023/06/17 07:17by 127.0.0.1