Craniofacial Bone Complex and Joints Flashcards
Human Skeleton
About 270 bones at birth Reduced to 206 by Adulthood
Axial Bones
Skull: _____ bones plus _____ associated bones
Torso: 52 bones
Appendicular bones
Upper extremities: 64 bones Lower extremities:62 bones
22
9
The Skull
_____: The region of the skull that encases the brain
_____:
The region of the skull that makes up the bones of the face
neurocranium
vicerocranium
Neurocranium
Cranial _____:
The portion of the skull that overlies the brain; It is formed by _____ ossification
Cranial _____:
The portion which underlies the brain; It is formed through _____ ossification (_____)
vault intramembranous base endochondral chondrocranium
Membranous bones of the skull:
Membranous bones making up the calvarium of the skull are each derived from the _____ ossification center.
how membranous bones develop
week _____: bony spicules, ossification centers grow outward and then they meet; the area where they meet never really _____ > develops into the cranial _____
occipital, parietal, frontal, maxilla, mandible, nasal bone
primary
6-7
ossifies
sutures
Development of Cranial base: Chondrocranium
Cartilaginous precursors of the cranial base, several small cartilages form a central stem and other cartilages outline paired lateral structures, begin to appear at about _____ weeks of development in the mesoderm or ectomesenchyme separating the brain above from the rest.
The chondrocranium is fully fused and differentiated by the end of the _____ month of pregnancy, or _____ weeks since the initiation of cartilage formation.
Mineralization of the chondrocranium takes place at various centres of
ossification that appear in the cartilages of the cranial base
7
second
2
Alveolar process of maxilla
alveolar process - teeth are embedded; different from the rest of bone, develops in a different _____; present only when teeth are present, when no teeth > it _____ and _____
manner
regresses
disappears
Prenatal Growth and Development of Maxilla:
- Maxilla forms within the maxillary _____ extending ventrally from the _____ arch
- _____ ossification
- Ossification starts in _____ week
- _____ development
mandibular arch is the _____ brachial arch > has a maxillary process that extends and forms the upper face; ossification begins here
brachial arch is _____ (maxilla is derived from neural crest)
prominences mandibular intramembranous 7th palatal
first
neural crest
Postnatal Growth and Development :
Two Basic Modes of Growth Movements
- Remodeling:
Deposition and resorption of bone
(a) _____
(b) _____ - Displacement:
Growth movements which cause separation of the different bones
(a) _____
(b) Cranial base _____
cortical drift
relocation
sutural growth
synchondrosis
Postnatal Growth and Development
intramembranous > bone is added on the surface, only grows by _____ growth
as you go from immature to mature bone; you must ____ (cortical drift/relocation)
appositional
remodel
Remodeling and Relocation vs. Cortical Drift
EXPLAIN ME
YES
Remodeling of Palate
ü Bone ____ on oral side
ü Bone ____ on nasal side
deposition
resorption
know that the maxilla (maxillary tuberosity, alveolar processes) grows via a ____ process
remodeling
Mandible
mandibular notch, when condyle is absorbed in arthritis, you will see changes in the mandibular ____
notch
Mandible: Prenatal Growth & Development
- ____ week in uterine
- ____ & ____ ossification
6th
intramembranous
endochondral
Body:
The mandible is ossified in the fibrous membrane covering the outer surfaces of ____ (6th wk)
meckel’s cartilage forms the original ____, but never turns into the mandible; serves strictly as the ____ structure; formed by ____ ossification
meckel’s cartilages
temple
positioning
intramembranous
Ramus:
The condylar cartilage - Carrot shaped cartilage appears (____ wk) in the region of the condyle and occupies most of the developing ramus. Converts to bone by ____ ossification (____ wk), forming condyle head and neck.
Coronoid process - A small strip of cartilage appears along the anterior border of the coronoid process. It is invaded by the surrounding membrane bone and undergo absorption (____ wk).
condylar cartilage is maintained until ____; cartilage in coronoid process ____
10th
endochondral
14th
10-14th
puberty
regresses
Alveolar Bone
It starts when the deciduous tooth germs reach the early ____ stage. The bone of the mandible begins to grow on each side of the tooth germ.
The alveolar processes grow at a rapid rate during the periods of ____.
bell
tooth eruption
Mandible: Postnatal Growth & Development
Main Growth Sites:
ü Secondary Cartilage (____ Cartilage)
ü ____ Ridge
ü The Ramus
ü Lingual ____
condylar
alveolar
tuberosity
- Condylar Cartilage:
• ____ cartilage
• Functions as ____ cartilage and ____ site (which is why it is formed by both intra/endo ossification).
• Adoptive response to mechanical ____ and development
• Growth of condylar cartilage helps in:
- Increase in ____ of the mandibular ramus
- Increase in the overall ____ of the mandible
- Increase of the inter condylar distance (____) - Growth with the alveolar process:
• Due to the increase in the space between the upper and lower jaws a space created between the opposing teeth to erupt. This means that bone deposition contributes to the growth of the body of the mandible in ____.
secondary articular growth stress height length width
height
- Ramus:
Periosteal bone apposition and resorption (bone remodeling) help in mandible growth. The results depend on the place of bone remodeling. Growth can occur in ____, ____ and ____
Move posteriorly by bone deposition on ____ border and resorption on ____ border. The anterior part of the ramus becomes the ____
height
length
width
posterior
anterior
corpus
Width
Completed before ____ growth spurt at around age ____
Length
Continues through puberty
- Girls: ____ years
- Boys: ____ years
Height
Continues into ____ after the growth spurt
large mandible > jaw surgery > you want it to be passed the time of length completion (girls for 16, boys closer for 20)
height growth until adulthood becomes a problem for placing dental implant in teenagers (18 y.o.); the dental implant will still behind, nowadays implants are placed much later on (girls 20, boys even later)
adolescent
12
14-15
18-19
adult
Jaw Alignment
Class I = ____
Class II = ____
Class III = ____
class III > if overgrown mandible, postpone surgery because mandible continues to grow until later in life (bc has it’s own growth potential)
balanced jaw relationship
underdeveloped mandible
overgrown mandible/underdeveloped maxilla
JOINTS in the SKULL • \_\_\_\_ • Sutures • \_\_\_\_ • Gomphosis
TMJ is not identical to other synovial joints in the body; synovial joints in the skull are ____
not unique joint structure in skull > synchondroses/sutures (____ and ____ are unique in skull)
synchondroses
synovial joint
unique
synovial joints
gomphosis
Synchondrosis
- A union between two bones by the formation of either ____ cartilage or ____ cartilage
- Usually ____ and exists during the growing phase until the intervening cartilage becomes progressively ____ and ultimately becomes obliterated and converted into bone before adult life
hyaline
fibro
temporary
thinner
