Lecture 9: Formation of Mandible & TMJ Flashcards
initial appearance of bone tissue in each of the bones of body
ossification centers
ossification centers within mesenchyme and cartilage
mesenchyme: intramembranous bone organ development
cartilage: endochondral bone organ development
some bones, such as the temporal bones, have both intramembranous and endochondral ossification centers and are known as having what?
mixed ossification centers
addition of bone tissue to a bone organ
growth sites
- PDL is an example (cementum and bone)
- areas of cartilage
what are the 6 roles of meckel cartilage
*meckels cartilages serve as BOTH ossification centers of ear ossicles and as a growth site of each mandible half
- temporary skeleton of mandibular process
- temporary attactchment for mm that will attach to mandible
- each cartilage serves as models for 2 ear ossicles (malleus and incus)
- each serve as site for the appearance of 2 ligaments (ant. mallelar and sphenomandibular)
- temporary ant lingual plate of forming mandible halves
- serve as enclosed GROWTH SITES at chin end
what are the is the fate of the meckel’s cartilage?
*meckels cartilages serve as BOTH ossification centers of ear ossicles and as a growth site of each mandible half
from the proximal part (inner ear) to the distal part (chin), each cartilage serves sites for:
- endochondral ossification centers for 2 ear ossicles
- undergo retrogressive changes becoming 2 ligaments
- undergo growth, mineralization, and resorption while serving as ant. growth sites and replaced as temp ant mandible halves
when does the ossius union of the mandible occur?
end of first postnatal year
*development of mandible begins in the 6th embryonic week
explain the development of the mandible
2 bilateral ossification centers in mesenchymal tissue lateral to meckel’s cartilage appearing in the area where the inferior alveolar nerve branches. grows anteriorly (growth site of temp lingual palate) and posteriorly (growth site)
*condylar cartilages DO NOT arise from meckel’s cartilage
what does the proximal end of each meckel catilage become?
- malleus and incus ossicles
- ant. mallelar ligament
what does the middle area of each meckel cartilage become?
sphenomandibular ligament
what does the distal end of each meckel cartilage become?
- temporary ant lingual plate
- growth sites of the mandible halves
type of joint that permits little of no mobility (fibrous and suture joints)
synathrosis
btw maxillary bones, btw temporal and parietal bones
type of joint that permits slight mobility (cartilaginous joints)
pubic symphisys
type of joint that permits a variety of movements (synovial joint)
diarthrosis
TMJ
a joint that binds a tooth to a bone socket
gomphosis
