Tmj 1

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Tmj 1

  1. 1. Temporomandibular • Bilateral synovial Joint : TMJ articulation of the mandibular head and the temporal bone
  2. 2. Temporomandibular Joint : TMJ Synovial articulation between the mandible and the cranium Allows considerable movement and has a joint cavity filled with synovial fluid and is surrounded by a joint capsule Bones of the joint-1 articular disc-2 divides the joint cavity into upper lower compartment posterior bilaminar zone wraps around the joint compartment anterior bilaminar zone :Articular capsule-3
  3. 3. :Joint description • Type of joint • Bones involved , Ligaments • Disc • Capsule • Synovial membrane • Innervation • Blood supply • Muscles bringing about movement
  4. 4. :Type of joint Synovial: Bilateral diarthrosis permits great mobility Hinge, Sliding movement
  5. 5. :TMJ Consists of • 1-Bones mandibular condyle temporal bone Eminence • 2-Articular disc • 3-Capsular ligament • 4-Joint cavity Fossa
  6. 6. Segittal Section through the TMJ
  7. 7. Articular disc separates superior and inferior joint cavities
  8. 8. Articular Disc posterior bilaminar zone anterior bilaminar zone
  9. 9. • The disc is divided into three zones: • Anterior band – split into 2 lamellae: • -Upper lamella attached to articular eminence • -Lower lamella attached to condylar head • fibers of superior head of the lateral pterygoid inserted in between
  10. 10. –: Intermediate band • Thinnest central region which is avascular and .  has no innervation This zone is composed of fibrous connective • . tissue and is devoid of cells
  11. 11. : Posterior band • • : This region attaches posteriorly by a ( superior lamella(retrodiscal pad • attaches superiorly to the capsule and temporal - • ; bone highly vascular, innervated . (loose - • ( CT ,elastic fs., BV., nerves inferior lamella • attaches to the posterior aspect of the neck of - • .the condyle consists mainly collagenous fibers with no - • . elastic fibers
  12. 12. TMJ Ligaments temporomandibular ligament stylomandibular ligament Lateral view sphenomandibular ligament stylomandibular ligament Medial view
  13. 13. TMJ :Capsule •Envelops the joint •Thickened laterally: temporomandibular ligament
  14. 14. Temporomandi bular ligament
  15. 15. Histological Structure of TMJ .fibrous C.T .fibrous C.T inner zone intermediate z outer zone synovial membrane descending limb Trabeculae radiate from the center of condyle and reach the surface at right angles
  16. 16. Histological Structure of TMJ articular- 1 eminence fibrous-2 covering articular- 3 disc fibrous- 5 covering hyaline- 6 cartilage lower- 4 joint cavity cancellous- 7 bone
  17. 17. Articular surface of mandibular condyle (young) Articular surface of mandibular condyle (adult)
  18. 18. Articular Capsule outer fibrous layer inner Synovial membrane •thin C.T. •lined by synovial cells •intermingled with C.T. fibers • fibroblasts,histiocytes,lymphocytes •EM.:TypeA secrete hyaluronic acid Type B pr.rich secretion Synovial folds and villi
  19. 19. : The capsule consists of • Outer fibrous layer • .dense fibrous collagenous connective tissue- • (Inner synovial layer (synovial membrane lines the inner aspect of the capsule facing the. .two synovial spaces,has synovial villi • •
  20. 20. The Synovial Fluid • Clear, straw colored, viscous fluid • Infiltrate of the blood • Contains hyaluronic acid sectreted by synovial cells. • Contains free macrophages. Functions • Nutriant for the avascular tissue of the articulation • Lubricant for the articulating surfaces • Clears the tissue debris caused by the normal wear and tear of the articulating surfaces- from the articular cavity
  21. 21. Thick fibrous covering of the condyle with condroid changes Synovial folds become fibrotic with thick underlying b.m Age Changes of TMJ Flattening of the condyle Thin articular disc with hyalinization and chondroid changes Osteoporosis of the underlying bone Thining of the cartilagenous zone of the condyle decreased synovial fluid loss of lubrication Dysfunction of TMJ in old age Decreased extensibility of the disc and capsule Decreased nerves in disc and capsule
  22. 22. Innervation : of TMJ Blood Supply of TMJ - Trigeminal n.- mandibular Auriculotemporal Masseteric n Internal maxillary artery Deep auricular Superfecial temporal Pterygoid plexus- venous drainage Vascular plexus in the wall of the capsule- production of synovial fluid

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