mandible and TMJ Flashcards

1
Q

meckel’s cartilage

A

in each mandibular process of BA 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the roles of meckel’s cartilage

A
  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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

fate of meckels cartilage

A
  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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is an ossification center

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

where can ossification centers appear

A
  1. w/in mesenchyme

2. on or w/in cartilage model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

if ossification centers appear w/in mesenchyme it is called

A

intramembranous bone organ development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

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

A

endochondral bone organ development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

do the # of ossification centers vary from bone to bone

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how many o.cs does the mandible have

A

1 for each half

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how many o.cs does the maxilla have

A

2 in each bone…so 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

mandible and maxilla development are examples of

A

intramembranous ossification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are growth sites

A

addition of bone tissue to a bone organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

intramembranous bone tissue

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

the PDL is a

A

growth site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

when does the mandible begin development

A

6th embryonic week

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

where does the mandible arise from

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

where do the ossification centers appear

A

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

18
Q

bone tissue grows

A

anterior to posterior from the center

19
Q

how does the anterior mandible grow

A

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

20
Q

the incorporated part of each cartilage becomes

A

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

21
Q

how does the posterior mandible grow

A

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

22
Q

the hyaline cartilage incorporated by the posterior mandible becomes

A

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

23
Q

does the condylar cartilage arise from meckel’s cartilage

A

no

24
Q

when does osseous union occur

A

first postnatal year

25
Q

proximal end of MC serves as a model for

A

malleus and incus and anterior mallelar ligament

26
Q

the middle area of MC serves as a model for

A

sphenomandibular ligament

27
Q

the distal end of MC serves as a model for

A

temp anterior lingual plate and growth site of growing mandibular halves

28
Q

the mylohyoid is attached to the

A

medial sides of MC

29
Q

malleus and incus form via

A

endochondral ossification

30
Q

what type of joint is a tooth in a bone socket

A

gomphosis

31
Q

what type of joint is the maxilla

A

synarthrosis…little or no mobility

32
Q

what type of joint is the TMJ

A

diarthrosis..freely moveable

33
Q

what 2 bones make up the TMJ

A
  1. squamous portion of the temporal bone

2. condyloid process of the mandible

34
Q

unique features of the TMJ

A
  1. complete articular disk
  2. joint cavities
  3. soft c.t articulating surfaces
35
Q

TMJ starts formation with the appearance of a

A

blastema…site of condylar cartilate appearance and the articular disc

36
Q

when does the blastema appear

A

8 week embryo

37
Q

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

A

3rd month in utero

38
Q

how long does the condylar cartilage remain

A

age 25

39
Q

what is a blastema

A

rudimentary substance from which cells, tissues, organs are formed

40
Q

what forms from the TMJ blastema

A

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