Temporomandibular joint and Muscles of Mastication Dr. Sama ul Haque

1. Temporomandibular joint and Muscles of Mastication Dr. Sama ul Haque

2. Objectives • Identify the parts of the mandible. • Know the type and formation of temporomandibular joint. • Understand the attachment of the capsule and ligaments of the temporomandibular joint. • Explain the mechanism of movements taking place at temporomandibular joint. • Define the stability factors of the joint. • Explain the muscles of mastication with their origin, insertion, nerve supply and actions. • Discuss maxillary artery.

3. Mandible

4. Mandible (Outer aspect)

5. Mandible (Inner aspect)

6. Temporo-Mandibular Joint (TMJ) • Mandibular fossa of temporal bone with condyle of mandible • Two joint cavities with articular disc interposed • Lower cavity = hinge joint • Upper joint = gliding

7. TMJ

8. TMJ • Capsule • Surrounds the joint • Encloses the disc • Attaches above the margins of the mandibular fossa • To the neck of the mandible • Inner aspect of capsule attaches to disc • Above disc – capsule loose • Below disc - taut

9. TMJ Capsule & Ligaments

10. TMJ Joint Cavity

11. TMJ • Movements • Elevation • Depression • Retraction • Protraction • Side to side

12. TMJ Motions

13. TMJ • Side to side – grinding movements • Mandible is alternately protracted and retracted with the two sides moving in opposite directions so that one side is protracted while the other is retracted • Actions combined with elevation and depression, rhythmically and alternately

14. Muscles of Mastication • 1. Masseter • 2. Temporalis • 3. Lateral pterygoid • 4. Medial pterygoid • All innervated by CN V (Trigeminal) • Opening of jaw (depression) primarily passive or gravity assist.

16. Masseter

17. Temporalis

18. Pterygoids

19. Pterygoids

20. Pterygoids

21. TMJ Motions

22. Maxillary Artery

23. Maxillary Artery

24. Thank you