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Flashcards in mandible and TMJ Deck (40):
1

meckel's cartilage

in each mandibular process of BA 1

2

what are the roles of meckel's cartilage

1. temp skeleton of man. processes of BA 1
2. temp attachment for mm that eventually attach to the mandible
3. cartilage models/OSSIFICATION CENTERS for the malleus and incus
4. appearance site of 2 ligaments (anterior mallelar and sphenomandibular)
5. temp anterior lingual plate of forming mandible halves
6. serve as enclosed GROWTH SITES at the chin end of the mandible

3

fate of meckels cartilage

1. endochondral ossification centers for the 2 ossicles
2. retrogressive changes to become the 2 ligaments
3. undergo growth, mineralization and resorption while serving as an ANTERIOR GROWTH SITE and replaced as temporary anterior lingual plate by the encroaching bone tissue of the growing mandible halve

4

what is an ossification center

initial appearances of bone tissue in the area where each of the bone organs of the body form

5

where can ossification centers appear

1. w/in mesenchyme
2. on or w/in cartilage model

6

if ossification centers appear w/in mesenchyme it is called

intramembranous bone organ development

7

if ossification centers appear on or w/in a cartilage model it is called

endochondral bone organ development

8

do the # of ossification centers vary from bone to bone

yes

9

how many o.cs does the mandible have

1 for each half

10

how many o.cs does the maxilla have

2 in each bone...so 4

11

mandible and maxilla development are examples of

intramembranous ossification

12

what are growth sites

addition of bone tissue to a bone organ

13

intramembranous bone tissue

bone tissue always forms in a highly vascular c.t called intramembranous bone tissue

14

the PDL is a

growth site

15

when does the mandible begin development

6th embryonic week

16

where does the mandible arise from

from 2 bilateral ossification centers within mesenchymal tissue (intramembranous) lateral to meckel's

17

where do the ossification centers appear

in the area where the inferior alveolar nerve branches into the mental and incisive nerves (future mental foramina)

18

bone tissue grows

anterior to posterior from the center

19

how does the anterior mandible grow

the bone incorporates the distal parts (chin) of meckel's cartilage

20

the incorporated part of each cartilage becomes

the temp lingual plate and a GROWTH SITE of each mandible half

21

how does the posterior mandible grow

the posterior end of the facial plate incorporates an independent piece of hyaline cartilage

22

the hyaline cartilage incorporated by the posterior mandible becomes

the condylar cartilage which is a GROWTH SITE of each mandible half

23

does the condylar cartilage arise from meckel's cartilage

no

24

when does osseous union occur

first postnatal year

25

proximal end of MC serves as a model for

malleus and incus and anterior mallelar ligament

26

the middle area of MC serves as a model for

sphenomandibular ligament

27

the distal end of MC serves as a model for

temp anterior lingual plate and growth site of growing mandibular halves

28

the mylohyoid is attached to the

medial sides of MC

29

malleus and incus form via

endochondral ossification

30

what type of joint is a tooth in a bone socket

gomphosis

31

what type of joint is the maxilla

synarthrosis...little or no mobility

32

what type of joint is the TMJ

diarthrosis..freely moveable

33

what 2 bones make up the TMJ

1. squamous portion of the temporal bone
2. condyloid process of the mandible

34

unique features of the TMJ

1. complete articular disk
2. joint cavities
3. soft c.t articulating surfaces

35

TMJ starts formation with the appearance of a

blastema...site of condylar cartilate appearance and the articular disc

36

when does the blastema appear

8 week embryo

37

when does cavitation of the blastema occurs in the embryo for the TMJ

3rd month in utero

38

how long does the condylar cartilage remain

age 25

39

what is a blastema

rudimentary substance from which cells, tissues, organs are formed

40

what forms from the TMJ blastema

joint cavities (2)..condylar cartilage, articular disc, soft tissue articular surfaces