Temporomandibular Joint (TMJ)

Exam 4, DLA 1210

1. Temporomandibular Joint (TMJ) Chapter 22

2. Anatomy Joint is the joining together of two bones Temporomandibular joint (TMJ) is articulating joint between temporal bone (skull) and mandible (lower jaw) Bilateral movement of right and left sides interrelated and function as single unit The articular disc separates the joint into upper and lower compartments

3. Anatomy The condoyle of the mandible articulates with the mandibular ( glenoid ) fossa Location is the posterior slope of the articular eminence and anterior portion of the mandibular fossa Does not fit into the center of the mandibular fossa but rests near the articular (eminence) tubercle Articular disc (meniscus) rests between them

4. Anatomy

5. Anatomy The articular disc is a pad of dense fibrous connective tissue that is thickest at the posterior ends, thinnest in the middle, and thicker again at the anterior end. It separates the TMJ into upper and lower joint compartments. Laterally and medially, the disc is attached to the condyle itself, so that whenever the condyle glides forward and backward the disc moves with it.

6. Anatomy The condyle and articular eminence are covered by dense connective tissue Contains no blood vessels or nerves Nourished and lubricated by synovial fluid Joint is covered by a thick fibrous capsule The articular disc and capsule are connected by a retrodiscal pad A pad of loose connective tissue that allows for anterior movement of the joint

7. Anatomy

8. Nerve and Blood Supply Innervation supplied by two nerves Auriculotemporal and Masseteric Branches of mandibular nerve (V3) Blood supply provided by branches of superficial temporal and maxillary arteries

9. Movement Two types of movement in TMJ Hinge motion occurs in lower joint compartment between the disc and the condoyle Anterior gliding takes place in the upper joint compartment between the disc and the temporal bone The lateral pterygoid muscle causes the forward movement

10. Movement Closing of the mouth is accomplished by the lateral pterygoid muscle, which controls posterior movement of disc

11. Clinical Considerations An Internal Derangement occurs when the disc becomes stuck or displaced. As the condyle rotates and translates forward down the slope of the articular eminence, the disc should stay interposed between these bones. If it becomes displaced or stuck, sounds of clicking, popping or crepitus (crunching) may result.

12. Clinical Concerns Catching or locking of the jaw, subluxation The condoyle is displaced anteriorly and cannot be returned voluntarily to normal position Temporomandibular disorder (TMD), characterized by muscle soreness Bruxism (teeth grinding) from stress or tension are usual causes

13. Clinical Concerns Inflammation - arthritis may result from wear or tear within the joint Can also be a result of systemic disease like rheumatoid arthritis Cortisone is used to alleviate the pain of arthritis

14. Clinical Concerns

15. TMD https:// youtu.be/mB468Jh9aAY https:// youtu.be/Cj3GVRlrgEQ

16. Suggested Homework Answer the questions on pages 294-295 in your textbook. Complete pages 76-81 in your coloring book