Temporomandibular joints and their Functions

1. Temporomandibular joints and their Functions Introduction Like any other part of the body, evaluation has also taken place in TMJ the joint or Articulation is a connection B/w two separate parts of the Skelton. TMJ is the Articulation B/w the mandible and two temporal bones this mandibular Articulation with the skull on each side is also known As craniomandibular Articulation or joint. It is a bilateral Articulatin the right and left half work as signal unit. Reflexes control this complex movement. The adaptability of the joints permit the movement of the mandible which is required During speech and mastication proper function of TMJ has a great effect on the occlusion contact of the teeth

2. Anatomy of TMJ • Temporomandibular joint is , it has three Articulating parts • 1-the mandiblar condoyle • 2-Articular fossa and eminence of Temporal bone • 3-Articulat Disc the Articular disc is interposed B/w bony parts • All these parts are incused by fibrous connective tissue capsul

3. Mandibular condoyle • The mandibular condoyle is large and solid structure .On average it is 10mm thick Anteroposteriorlly and it is knob like form is 20.4mm wide mediolaterally the articulating surface or functioning part of the condoyle is located on the superior and Anterior surface of the head of the condoyle process of the mandibal • The surface condoyle is covered or lined with a thickened muscular layer of fibrous connective tissue the fibrous layers of the joint are vascular. • So that it indicates that a large Amount of force works on the joint it adapted to resist pressure

4. articular fosse • the Articular fosse is anterior three-fourths of the large mandibular fosse • this is nonfunctional portion of the joint B/c when the teeth are in tight Occlusion • there is no tight contact B/w the head of condoyle, the disc and concave parte of articular fosse the articular eminence or ridge is located anterior and below the anterior fosse

5. Thicker layer of fibrous connective tissue is present on it’s surface it indicates that it is the functional portion of joint the blood vessels and nerve supply are not present in this thickened portion the thickest functional part of the lining is the poster inferior part e articular eminence

6. Articular Disc • The Articular Disc also called as interaticular disc is a tough oval dense fibrous connective tissue it is located B/w the mandibular condoyle,articular fosse and articular imminence it is thinner in the center than around the edges it also thin anteriorly and laterally and thicker medially and posterior the center of the disc has no blood • The functions of articular disc

7. The functions of articular disc • 1- it divides the complex condylar movement into the upper and lower functional component • 2- it lubricates the joint with synovial fluid • 3- it stabilizes the condyle by filling the space B/w the articular surface • 4- At the point of contact of the joint it acts as a cushion to bear the load • 5 -it reduces physical wear and strain on the joint surface • 6- it helps to regulate movement of the condyle

8. Inner layer (synovial membrane) • It lines the capsule .it is thin layer and secretes a fluid synovial which lubricates the join and also nourishes it

9. Outer layer • It is thick layer Accessory ligament strengthens it • Anterior part of the capsule restricts posterior movement of the condoyle