the most impotent function of tempromendibular joint

the most impotent function of tempromendibular join

1. TeMPOROMANDIBULAR JOINT Dr. Ritika Chaudhary P.G. 1 st Year Department of Conservative Dentistry & Endodontics 1

2. Contents TEMPOROMANDIBULAR JOINT 1- Introduction Anatomy Blood and Nerve Supply Ligaments Temporomandibular Joint disorders 2

3. INTRODUCTION : The most important functions of the temporomandibular joint (TMJ) are mastication and speech and are of great interest to dentist, clinicians and radiologists. The TMJ is a ginglymoarthrodial joint, a term derived from ginglymus, meaning a hinge joint, allowing motion only backward and forward in one plane, and arthrodial meaning a joint which permits a gliding motion of the surfaces. 3

4. THE TEMPOROMANDIBULAR JOINT (TMJ) : is a gingylmodiarthrodial joint Has hinge-type of movements and gliding movements. Mandibular condyle forms the lower part of the bony joint . Articulation is formed by the mandibular condyle occupying a hollow in the temporal bone(Mandibular or Glenoid Fossa). 4 LIGAMENT DISK ARTICULAR FOSSA MUSCLE CONDYLE AREA OF DETAIL

5. DEVELOPMENT OF TMJ : The TMJ develops from mesenchyme lying between the developing mandibular condyle below and the bone above, which develop intramembranously. During the 12 th week of IU life ,2 clefts appear in the mesenchyme – producing the upper and lower joint cavities. 5

6. The remaining intervening mesenchyme becomes the intra – articular disc. The joint capsule develops from condensation of mesenchyme surrounding the developing joint. Mandibular fossa is flat at birth and there is no articular eminence , this becomes prominent only following the eruption of the decidous dentition. 6

7. 4 anatomical parts concerned with mandibular articulation: Mandibular condyle Mandibular fossa and articular eminence The articular disc The articular capsule 7

8. 8

9. Barrel shape Perpendicular to ascending ramus of the mandible Oriented 10 – 30 degrees with frontal plane. MANDIBULAR CONDYLE CORONOID PROCESS (Attachment for Temporalis muscle.) Pterygoid Fossa (attachment for Lateral Pterygoid muscle) Temporalis Muscle Medial Pterygoid muscle Mental Foramen Angle Masseter Muscle Mandibular Condyle Mandibular Notch RAMUS BODY 9

10. MANDIBULAR FOSSA AND ARTICULAR EMINENCE : Anterior aspect : articular eminence Posterior : non articular fossa Is a part of temporal squama and is formed by tympanic plate which also forms the anterior bony wall of external auditory meatus. At the posterior border of the fossa – a tubercle or cone shaped process present laterally between tympanic bone and fossa. This prevents direct impingement of condyle on the tympanic plate. The medial border of articular fossa : also contains a bony lip which extends into angular spine of sphenoid bone . These two bone processes or lips limit condylar displacement distally and laterally as well as vertically. 10

11. Biconcave oval structure interposed between the condyle of the mandible and the glenoid fossa of the temporal bone. The articular surface of the temporal bone has: Posterior concave part – mandibular fossa Anterior convex part – articular tubercle or eminence UPPER SYNOVIAL CAVITY LOWER SYNOVIAL CAVITY ARTICULAR DISC CAPSULE CAPSULE DISC ATTACHMENT TO MEDIAL AND LATERAL POLES OF CONDYLE ARTICULAR DISC : 11

12. An articular disc separates the articular surfaces so that 2 cavities are present: Upper compartment between the disc and temporal bone. Lower compartment between the condyle and the disc. 12

13. ARTICULAR CAPSULE (FIBROUS CAPSULE) Thin sleeve of tissue completely surrounding the joint. Extends from the circumference of the cranial articular surface to the neck of the mandible. 13

14. Most innervation is provided by the auriculotemporal nerve as it leaves the mandibular nerve behind the joint and ascends laterally and superiorly to wrap around the posterior region of the joint. Additional innervations by – deep temporal and massetric nerve. NERVE SUPPLY OF TMJ : 14

15. Superficial temporal artery - from the posterior Middle meningeal artery - from the anterior Internal maxillary artery – from the inferior Other important arteries are – the deep auricular ,anterior tympanic and ascending pharyngeal arteries. The condyle – through marrow spaces by way of the inferior alveolar artery . SUPERFICIAL TEMPORAL ARTERY BLOOD SUPPLY OF TMJ : INTERNAL MAXILLARY ARTERY MASSETRIC DEEP TEMPORAL MIDDLE MENINGEAL ARTERY 15

16. Made up of collagenous connective tissue 3 Functional ligaments support the TMJ : Collateral ligaments Capsular ligament TM ligament 2 Accessory ligaments Sphenomandibular ligament Stylomandibular ligament LIGAMENTS SUPPORTING TMJ : 16

17. COLLATERAL (DISCAL) LIGAMENT Composed of collagenous connective tissue fibres , Attach the medial and lateral borders of the articular disc to the poles of the condyle. 17

18. Medial discal ligament – attaches the medial edge of the disc to the medial pole of the condyle. Lateral discal ligament – attaches the lateral edge of the disc to the lateral pole of the condyle, DISCAL LIGAMENTS MEDIAL LATERAL These ligaments divide the joint mediolaterally into the superior and inferior joint cavities. Are responsible for the hinging movement of the TMJ , which occurs between the condyle and the articular disc. 18

19. CAPSULAR LIGAMENT : FIBROUS CAPSULE OF TMJ LATERAL LIGAMENT STYLOMANDIBULAR LIGAMENT ANGLE OF MANDIBLE 19

20. The fibres of the capsular ligament are attached superiorly to the temporal bone along the borders of the articular surface of the mandibular fossa and articular eminence Resists any medial, lateral or inferior forces that tend to separate or dislocate the articular surfaces. Significant function – to encompass the joint thus retaining the synovial fluid. 20

21. TEMPOROMANDIBULAR LIGAMENT : The lateral aspect of the capsular ligament is reinforced by strong, tight fibres – lateral ligament or TM ligament. LATERAL LIGAMENT STYLOMANDIBULAR LIGAMENT SPENOMANDIBULAR LIGAMENT CAPSULE 21

22. SPHENOMANDIBULAR LIGAMENT : ACCESORY LIGAMENT OF THE TMJ SPHENOMANDIBULAR LIGAMENT MYLOHYOID SULCUS STYLOID PROCESS STYLOMANDIBULAR LIGAMENT Arises from the spine of the sphenoid bone and extends downwards to a small bone prominence on the medial surface of the ramus of the mandible called the lingula. 22

23. STYLOMANDIBULAR LIGAMENT : SPHENOMANDIBULAR LIGAMENT MYLOHYOID SULCUS STYLOID PROCESS STYLOMANDIBULAR LIGAMENT 23

24. It arises from the styloid process and extends downwards and forward to the angle and posterior border of the ramus of the mandible. The stylomandibular ligament, limits the excessive protrusive movements of the mandible. 24

25. TEMPOROMANDIBULAR JOINT MOVEMENTS : Rotational/ Hinge movement in first 20-25mm of mouth opening. Translational movement after that when the mouth is excessively opened. 25

26. MUSCLE INVOLVED IN MOVEMENTS : Depression Lateral pterygoid, Digastric, Geniohyoid, Mylohyoid Elevation Temporalis, Masseter, Medial pterygoid Protrusion Medial pterygoid, lateral pterygoid Retraction Posterior fibres of temporalis 26

27. 27

28. HINGE MOVEMENT : the inferior portion of the joint between the head of the condyle and the lower surface of the disc to permit opening of the mandible. 28

29. AGE CHANGES OF THE TMJ : CONDYLE : Becomes more flattened Fibrous capsule becomes thicker Osteoporosis of underlying bone DISK : Becomes thinner Shows hyalinization and chondroid changes SYNOVIAL FLUID : Becomes fibrotic with thick basement membrane 29

30. ETIOLOGIC CONSIDERATIONS FOR TMD : 5 major factors associated with TMD : 1- Occlusal condition 2- Trauma 3- Emotional Stress 4- Deep pain input 5- Para-functional activities 30

31. OCCLUSAL CONDITION : Excessive load on the system due to orthopedic instability may lead to intracapsular disorders. 2 factors that determine it are : degree of instability and amount of loading Changes can be acute/sudden or chronic 31

32. TRAUMA : Macro and Micro MACRO : Sudden face that can result in structural alterations : Eg blow to face MICRO : small force applied repeatedly to structures over a long periods. Bruxism/clenching. 32

33. DEEP PAIN INPUT : Centrally excites a brainstem - produces muscle response-productive co-contraction. Functional disorders of masticatory system 2 symptoms - Pain and dysfunction 33

34. TMJ DISLOCATION : The mandible can dislocate in the anterior, posterior, lateral, or superior position. Anterior dislocations are the most common, these dislocations are classified as acute, chronic recurrent or chronic. TMJ dislocation may occur with trauma, extreme opening of the mouth during yawning, laughing, singing, vomiting or dental treatment. Symmetric mandibular dislocation is most common but unilateral dislocation with the jaw deviating to the opposite side also can occur. TMJ dislocation is painful and frightening for the patient. 34

35. LAB INVESTIGATIONS : Blood Tests : ESR, CRP for inflammation. Plain radiographs- show gross bony pathology such as degeneration or trauma. CT or MRI scan of the joint - MRI scan shows the soft tissues and intra-articular disc well. Ultrasound - this is a useful alternative imaging technique for monitoring TMJ disorders. Diagnose nerve block Arthroscopy 35

36. TMJ ANKYLOSIS : Ankylosis of the TMJ most often results from trauma or injection. True bilateral congenital ankylosis of the TMJ leads to micrognathia or "bird face". If ankylosis affects only one side, it produces a lateral deviation of the jaw to the non-affected side, due to the fact that this side continues its growth normally. 36

37. MANAGEMENT : Long term studies for TMD treatment have given 2 kinds of approaches : Conservative Reversible Therapy Counsel Exercise Physical therapy Medications Appliances Selective Grinding Non Conservative Reversible Therapy High Condylectomy Meniscectomy Disectomy Orthodontic surgery High Condylotomy 37

38. DEFINITIVE TREATMENT : Occlusal conditions - occlusal therapy(occlusal splint) Reversible - Stabilization appliance Irreversible - selective grinding, restorative procedures. Emotional Stress 0- Restrictive use, Voluntary avoidance, Relaxation therapy 38

39. SUPPORTIVE THERAPY : Directed toward the reduction of pain and dysfunction. Pharmacologic or Physical therapy : Analgesics NSAID's Corticosteroids Muscle relaxants Antidepressants 39

40. References : BD CHAURASIA HUMAN ANATOMY -2 ND EDITION GRAY’S ANATOMY- 2 ND EDITION ANAND’S HUMAN ANATOMY- 2 ND EDITION INDERBER SINGH- TEXTBOOK OF ANATOMY -5 TH EDITION 40

41. 41 THANK YOU