Lecture 5- anatomy of the TMJ

Question 1

what is the TMJ

Answer 1

where the mandible articulate with the base of the cranium

Question 2

what does the condyle of the mandible fit into

Answer 2

squamous part of the temporal bone- manidbular fossa, glenoid fossa, articular fossa

Question 3

what is a compound joint and what are the bones of the TMJ

Answer 3

more than three bones
-condyle, squamous temporal, articular disc

Question 4

what is a complex joint

Answer 4

allows for more than one type of movement

Question 5

what is the joint classification of the TMJ

Answer 5

compound joint
-complex joint
-synovial joint
-ginglymoarthrodial joint

Question 6

what is meant by ginglymoarthrodial joint

Answer 6

-ginglymoid joint implies hinge movement
-arthodial joint implies gliding movement
- so hinging and gliding

Question 7

what is the articular disc made of

Answer 7

dense fibrous connective tissue

Question 8

what is the shape of the articular disc

Answer 8

concave on the inferior part
- concavo-convex on the superior part

Question 9

is the articular disc innervated or have blood

Answer 9

no

Question 10

is the articular disc flexible

Answer 10

somewhat

Question 11

what are the 3 sections of the articular disc in a sagital section

Answer 11

-anterior zone (middle in thickness)
- middle or intermediate zone (thinnest)
- posterior (thickest)

Question 12

what does the articular surface of the condyle function as

Answer 12

the intermediate zone of the TMJ disc

Question 13

what is the articular disc divided into in a frontal section

Answer 13

medial and lateral

Question 14

which portion is thicker: medial or lateral

Answer 14

medial

Question 15

what do the discal/collateral ligaments attach the disc to

Answer 15

the medial and lateral poles of the condyle and the surrounding capsule

Question 16

what is the articular zone made of histologically and what is its purpose

Answer 16

dense fibrous connective tissue, less suscpetible to aging and better ability to repair, most superficial layer

Question 17

what is the proliferative zone made of histologically and what is its purpose

Answer 17

undifferentiated mesenchymal cells and is responsible for proliferation of articular cartilage in response to loads

Question 18

what is the fibrocartilaginous zone made of and what is its purpose

Answer 18

3D network of collagen offering resistance to lateral and compressive forces

Question 19

what is the calcified zone made of and what is its purpose

Answer 19

chondrocytes and chondroblasts
-active site for bone remodeling

Question 20

what are all areas of the synovial joint not involved in articulation covered with

Answer 20

specialized endothelial cells that form the synovial lining

Question 21

what do specialized endothelial cells that form the synovial lining produce

Answer 21

synovial fluid

Question 22

what is boundary lubrication and what does it do

Answer 22

movement of fluid from one area of the joint cavity to another
-prevents friction

Question 23

what is weeping lubrication

Answer 23

articular surfaces absorb some of the fluid
- increased absorption during function metabolic exchange

Question 24

what is the innervation of the synovial joint

Answer 24

mandibular branches of the trigeminal nerve- auriculotemporal and masseteric

Question 25

what is the vascularization of the synovial joint

Answer 25

superficial temporal artery - branch of the external carotid artery

Question 26

what are the disc attachments

Answer 26

-posteriorly -anteriorly -attached to capsular ligament anteriorly, posteriorly, medially, and laterally

Question 27

what are the posterior attachments of the disc

Answer 27

-superior retrodiscal lamina - inferior retrodiscal lamina

Question 28

describe the superior retrodiscal lamina

Answer 28

-attaches the articular disc to the tympanic plate -connective tissue - lots of elastic fibers - stretches as joint is moved forward

Question 29

describe the inferior retrodiscal lamina

Answer 29

-collagenous attachment (non elastic) - attaches the posterior margin of the articular surface of the condyle

Question 30

what are the anterior attachments of the disc

Answer 30

-superior head of the lateral pterygoid muscle -superior anterior attachment - inferior anterior attachment

Question 31

what does the superior anterior ligament attach

Answer 31

-to the capsular ligament - to the anterior margin of the articular surface of the temporal bone

Question 32

what does the inferior anterior attachment attach

Answer 32

-to the capsular ligament - to anterior margin of the articular surface of the condyle

Question 33

what is the superior joint cavity bordered by

Answer 33

-glenoid fossa - superior aspect of the disc

Question 34

what is the inferior joint cavity bordered by

Answer 34

-inferior aspect of the disc - superior aspect of the condyle

Question 35

where does rotation occur

Answer 35

in the inferior joint compartment

Question 36

where does translation occur

Answer 36

in the superior joint compartment

Question 37

what are the functional ligaments of the joint

Answer 37

-collateral/discal ligaments -capsular ligaments - TMJ ligament

Question 38

what are the accessory ligaments

Answer 38

-sphenomandibular ligament - stylomandibular ligament

Question 39

what is the capsule ligamnet/joint capsule attached to

Answer 39

-the base of the skull and the condyle - the periphery of the articular parts - the disc medially and laterally

Question 40

what does the capsular ligament do

Answer 40

surrounds the joint like a curtain - retains synovial fluid

Question 41

where is the TMJ ligament

Answer 41

-thickening of the capsular ligament on the lateral aspect -extends from the articular tubercle and zygomatic process to the lateral pole and neck of the condyle and the disc

Question 42

what are the two parts of the TMJ ligament

Answer 42

-outer oblique - inner horizontal

Question 43

what is the function of the outer oblique portion of the TMJ ligament

Answer 43

-prevents over rotation of the mandible -causes translation of the mandible after 20-25 mm opening

Question 44

what is the function of the inner horizontal part of the TMJ ligament

Answer 44

- limits posterior movement onto the highly innervated retrodiscal tissue (PAIN) - prevents excessive overextension of the lateral pterygoid muscle

Question 45

what does the sphenomandibular ligament arise from and what does it insert into

Answer 45

the spine of the sphenoid bone inserts onto the medial surface of the ramus of the mandible called the lingulua

Question 46

where does the stylomandibular ligament arise from and insert

Answer 46

arises from the styloid process inserts into the posterior border of the ramus of the mandible

Question 47

what is the function of the stylomandibular ligament

Answer 47

limits excessive protrusive movement of the mandible

Question 48

what is centric relation dependent on

Answer 48

TMJ not teeth