TMJ & Meckels cartilage Flashcards
___ ___ is the initial appearance of bone tissue in the area where each of the 206 Bone organs of the body form.
Ossification center
How many mandible and maxillae are formed of the 22 adult skull bone organs?
1 mandible and 2 maxillae
Where are the two areas that ossification centers appear?
within mesenchyme or on or within a cartilage model
If the ossification center appears within mesenchyme, what is it called?
intramembranous bone organ development
What is the ossification center called if it appears on or within a cartilage model?
endochondral bone organ development
How many ossification centers are found in the mandible and maxillae?
1 mandible = 2 ossification centers (1 for each halve)
2 maxillary bones = 2 ossification centers for each bone
Is it possible for some bones to have mixed ossification centers, both intramembraneous and endochondrial ossification centers?
yes
Define a growth site.
It is the addition of bone tissue to a bone organ
Growth sites for bone tissue formation include the periosteum, endosteium, haversian and volkman canals and the ___ ___.
periodontal ligament (PDL)
No matter what environment bone tissue forms in or on, it always forms within a highly ___ connective tissue that is referred to by some as ___ bone tissue.
vascular; intramembranous
Where are the paired Meckel Cartilages located?
One in each mandibular process of branchial arch I
The paired Meckel’s Cartilages serve as the temporary skeleton of the ___ processes of branchial arch ___.
mandibular; I
T/F. Meckel’s Cartilage does not attach muscles that will eventually attach to the mandible.
False, they serve as temporary attachments for muscles that eventually attach to the mandible
Each cartilage serves as models for 2 ear ossicles. What are they?
mallelus and incus
The meckel’s cartilage serves as a site for what two ligaments?
anterior mallelar and sphenomandibular
The Meckel’s cartilage serves as temporary ___ ___ plate of forming mandible halves.
anterior lingual
Meckel’s cartilage serves as an enclosed growth site at the ___ end of the mandible halves.
chin
Meckel’s cartilage extends from the proximal part of the ___ ear cavity to the distal part of the ___.
inner; chin
Meckel’s cartilage serve as both ___ ___ of ear ossicles and as a ___ ___ of each mandible halve.
ossification centers; growth site
T/F. The mandible develops as 3 bilateral halves that exist throughout the interuterine period.
False, The mandible develops as 2 bilateral halves that exist throughout the interuterine period.
When does the mandible begin to develop?
week 6
Where does the mandible arise from?
2 bilateral ossifciation centers witin mesenchymal tissue lateral to Meckel’s cartilages.
Where do the ossification centers appear?
in the area where the inferior alveolar nerve branches into the mental and incisive nerves or site of future mental foramina.
Anterior bone growth incorporates the ___ parts of Meckel’s cartilage. This part of each cartilage will become the temporary ____ plate and a ___ ___ of each mandible halve.
anterior; lingual; growth site
The ___ bone grows in the form of a ‘U’ featuring ___ and lingual plates.
posterior; facial
The posterior end of the facial plate incorporates what independentstructure that becomes the ‘condylar cartilage’, another growth site of each mandible half?
hyaline cartilage
T/F. Condylar cartilage arises from Meckel’s cartilage.
False, condylar cartilage does NOT arise from Meckel’s cartilage, it’s independent.
At the end of the first ___ year, an osseous union occurs between ___ mandibular halves at the ___ or chin site. Here, the mandible becomes 1 of the ___ skull bones.
postnatal; 2; distal; 22
Match:
A. Proximal end
B. Middle area
C. Distal end
- temporary anterior lingual plate
- malleus
- anterior mallelar ligament
- sphenomandibular ligament
- incus
- growth sites of the mandible halve
A - 2, 3, 5
B - 4
C- 1, 6
What muscle attach to the medial sides of Meckel’s cartilage?
mylohyoid muscle
Define a joint or articulation.
the place of union or junction between two or more bones of the skeleton
___ permits little or no mobility. Examples include fibrous and suture joints. These can be found between ___ bones, and temporal and parietal bones.
Synarthrosis; maxillary
___ permits slight mobility. Examples include ___ joints. This can be found in the pubis symphysis.
Amphiarthrosis; cartilaginous
___ permits a variety of movements. An example includes the synovial joints. This can be found in the ___ joint.
Diarthrosis; temporomandibular
What joint binds a tooth to a bone socket?
Gomphosis joint
Most freely movable joints include one joint ___, an incomplete ___ disc, and a ___ articular surface. These features are true for most freely moveable joints except what?
cavity; articular; cartilage
temporomandibular joint
What two bones form the temporomandibular joint?
temporal = squamous portion mandible = condyloid process (condyle)
What are the unique features of the temporomandibular joint?
complete articular disc
two joint cavities
soft connective tissue articulating surface
T/F. The blastema or rudiments of TMJ and site of condylar cartilage appear at week 8 of the embryo along with the cavitation.
False, blastema or rudiments of TMJ and site of condylar cartilage appear but NO cavitation in 8 week embryo
When does cavitation occur?
third month in utero
Appositional growth occurs between the ___ connective tissue surface and the ___ cartilage.
articular; condylar
What happens at the lower end of the hyaline cartilage?
the cartilage is mineralized, resorbed and replaced by bone tissue
The condylar cartilage remains until about the age of ___ when it is replaced by ___ bone tissue.
25; compact
What structure forms cells, tissues, or organs?
the blastema
The TMJ blastema forms ___ cartilage, ___ disc, ___ joint cavities, and soft tissue articular surfaces.
condylar; articular; two
