TMJ

Question 1

describe mandible growth

Answer 1

different parts grow in congruence with each other but in general tends to happen in anterior posterior direction as well as in a flaring direction

Question 2

what does an overdeveloped ramus/body do to the jaw

Answer 2

flat angle of jaw

Question 3

what does an underdeveloped ramus/body do to the jaw

Answer 3

steeper incline/angle of the jaw which can lead to crowding

Question 4

what are the TMJ innervation receptors and what do they each do

Answer 4

-ruffini corpuscles: proprioception
-pacinian corpuscle: dynamic mechnoreception (chewing)
- golgi tendon organs: static mechanoreceptors (rest)
- free nerve endings: detect pain

Question 5

what is the joint classification of the TMJ

Answer 5

synovial sliding ginglymoid joint

Question 6

what does a synovial joint do

Answer 6

permits movement between 2 bones

Question 7

what does the sliding joint classification of the TMJ describe

Answer 7

the second part of jaw opening, sliding anterior of the condyle over the glenoid fossa

Question 8

what does the ginglymoid joint classification of the TMJ describe

Answer 8

the first part of opening, hinge portion

Question 9

what is the joint cavity filled with

Answer 9

synovial fluid that is derived from villus cells which line the internal space of the capsule

Question 10

what does the fibrous disc do

Answer 10

separates the bones preventing damage

Question 11

how do the condylar neck and head develop

Answer 11

endochondral ossification

Question 12

what is multidirectional growth capacity

Answer 12

unlike long bones of the body the cartilage cells in the condylar head and neck do not exhibit ordered columns

Question 13

what does the fibrous capsule encapsulate

Answer 13

the entire joint

Question 14

what does the superior lateral pterygoid attach to

Answer 14

joint capsule and articular disc

Question 15

what does the inferior lateral pterygoid attach to

Answer 15

condylar neck in pterygoid fossa

Question 16

what is the glenoid fossa

Answer 16

bony part of the temporal bone that allows for articular surface of mandibular condyle to fit in

Question 17

describe the collagen fibers in the glenoid fossa

Answer 17

arranged in multiple directions allowing for a more robust surface of articulation

Question 18

what are the inner perpendicular collagen fibers on the posterior slope of the TMJs articular eminence responsible for

Answer 18

resisting compression of the mandibular condyle against the articular surface of bone

Question 19

how do the articulating surfaces of the TMJ change with age

Answer 19

covered with a layer of fibrous tissue, with increasing age the deeper portions of the fibrous covering may exhibit islands of cartilage

Question 20

how do the condylar heads of the TMJ change with age

Answer 20

the condylar head becomes less cellular

Question 21

how does the articular disc of the TMJ change with age

Answer 21

becomes more cellular

Question 22

what is the retrodiscal connective tissue made of

Answer 22

comprised of collagen and elastic fibrous connective tissue, fat cells, and is highly vascular

Question 23

what does the composition of the retrodiscal connective tissue allow for

Answer 23

mandible to move freely in an anterior motion

Question 24

is there articulation between the retrodiscal connective tissue and the condyle

Answer 24

no

Question 25

what do the elastic fibers of the retrodiscal connective tissue insert into posteriorly

Answer 25

petrotympanic fissure

Question 26

what do the elastic fibers of the retrodiscal connective tissue insert into anteriorly

Answer 26

superior head of the lateral pterygoid

Question 27

describe anterior dislocation of the disc

Answer 27

the disc is attached to the medial and lateral surfaces of the condyle but not the temporal bone. when the mandible moves the disc moves as well. movement of the disc back and forth can cause asymptomatic clicking sound present in 70% of population

Question 28

where is all articulation of the disc

Answer 28

on the fibrous portion/dense area

Question 29

what does the dense area of the disc restrict

Answer 29

the posterior movement of the mandible and maintains the condyle in the anterior part of the glenoid fossa

Question 30

what is the function of the synovial membrane and where is it located

Answer 30

function: necessary for sliding movement location: inner surface of the fibrous capsule

Question 31

what are the 3 distinct layers of tissue in the TMJ synovial membrane

Answer 31

-the most peripheral/external layer is the fibrous capsule of the joint - the intermediate layer is the vascular subintima - the most internal layer is termed the intimal layer

Question 32

what two cell types does the intimal layer contain and what do each do

Answer 32

-type A synovial cells: macrophage like cells that exhibit phagocytic functions and are capable of producing inflammatory cytokines such as interleukins or tumor necrosis factors -type B synovial cells: fibroblast like cells that synthesize hyaluronate which is a major component of the synovial fluid in the superior and inferior compartments of the joint

Question 33

what is hyaluronate

Answer 33

major part of slippery synovial fluid that allows for free movement of the joint

Question 34

what happens in inflammatory joint disease in chronic or acute traumas

Answer 34

type A cells fuse and transform into a mulitnucleated giant cell and function like osteoclasts, resorbing bone and cartilage and elevate cytokine levels

Question 35

if intense enough what can inflammatory joint disease reaction cause

Answer 35

resorption within spongiosa of head and neck with resorption occurring simultaneously on internal and external surfaces of the condyle

Question 36

what is the arachidonic acid pathway

Answer 36

trauma -> activation of arachidonic pathway -> leukotrienes, thromboxanes and prostaglandins activate type A cells -> increased IL and TNF -> macrophage/osteoclastic activity -> tissue destruction

Question 37

what is arthritic degeneration

Answer 37

flattened condylar head occurs due to osteoclastic activity causing an almost bone on bone contact due to lack of cartilage layer

Question 38

what are found on condylarheads in arthritic degeneration

Answer 38

osteophytes

Question 39

what is the result of the degeneration of tissue in arthritic degeneration

Answer 39

decreased vascularity found in the retrodiscal area leading to pain on function

Question 40

what is internal derangement and what does it result in

Answer 40

disc is trapped in the antero medial position leading to limited opening, pain, and clicking upon opening

Question 41

what is ankylosis

Answer 41

loss of articular coverings and synovial membranes lead to direct bone to bone fusion

Question 42

what is ankylosis caused by

Answer 42

untreated fracture

Question 43

what can anklyosis in the TMJ lead to

Answer 43

specific malocclusion issues

Question 44

what is the result of the activation of leukotrienes, prostaglandins, and thromboxane's activation of Type A cells

Answer 44

swelling, pain and vasoconstriction