CTB45 Principles of facial and bone growth Flashcards
This session aims to describe the mechanisms of facial and bone growth • By the end of this lecture you should be able to: – Describe postnatal growth patterns – Revise bone formation and remodelling – Discuss mechanisms of craniofacial growth and development.
What does growth mean?
2) What does development mean?
3) What are the 3 main stages of ontogenesis?
1) change in size
2) Ontogenetic changes over time
3) growht and differentiation of cells, morphogenesis (formation of initial shape), changes in the shape of bones- their proportions and relationships to each other
What age does neural growth finish?
8 yrs
Which grows faster maxilla or mandible?
maxilla growth is faster
true or false
bones grow by simple symmetrical enlargement
false
The mandible grows by elongation of ____a___ and ___b___ in a posterior and
superior direction; and the ____c___ lengthens.
a) b) condyle and ramus
c) body of the mandible
What bones part of the neurocranium are part of chondrocranium?
2) what type of ossificaiton?
occipital, sphenoid, ethmoid, petrous and mastoid part of temporal
2) endochondral
What bones part of the neurocranium are part of membranous neurocranium?
2) What type of ossificaiton
1) interparietal part of occipital, parietal, frontal, squamous part of temporal
2) intramembranous
What type of offisification:
occipital, sphenoid,
endochondral
What type of offisification:
ethmoid, petrous and mastoid part of temporal
endochondral
What type of offisification:
squamous part of temporal
intramembranous
What type of offisification:
interparietal part of occipital, parietal, frontal,
intramembranous
what type of ossification:
vomer, palatine, zygomatic, mandible,
intramembranous
how do they form:
1) meckel’s cartilage
2) malleus
3) incus
1)2)3) endochnodral ossifcaiton (as all part of pharyngeal arch 1
What is formed from pharyngeal arch 1:
1) meckel’s cartilage
2) malleus
3) incus
What is formed from pharyngeal arch 2:
1) Reichert’s cartilage
2) stape
3) styloid process
how do they form:
1) Reichert’s cartilage
2) stape
3) styloid process
1)2)3) endochnodral ossifcaiton (as all part of pharyngeal arch 2
intra or endochon:
1) -supraoccipital
2) interparietal bone of occipital
3) exoccipital
4) basioccipital
1) enchon
2) intramembranous
3) enchon
4) enchon
intra or endochon
1) body of sphenoid
2) greater and lesser wing of sphenoid
3) last pterygoid plate of sphenoid
4) medial pterygoid plate of sphenoid
1) 2)3) endo
4) intramembran
what type ossification forms
a) epiphyseal cc
b) condylar cc
2) describe position of cells
1) a) endo
b) intra
2) a) aligned in columns
b) random (as multidirectional growth)
what is formed in epiphyseal cc, and by what?
Hyaline cartilage formed by chondrocyte
proliferation, maturation, hypertrophy;
Condylar cartilage: \_\_\_A\_\_\_ zone is continuous with mandibular periosteum. \_\_\_b\_\_\_ cells respond to functional loading and proliferate and differentiate to form \_\_\_\_c\_\_\_
a) Fibrous articular
b) Mesenchymal
c) chondrocytes
difference between bone relocation and bone displacement
- Relocation: Bone deposition and resorption on opposing surfaces causes a bone to
move (“drift”) in space (→ towards the side of deposition). - Displacement: External forces generated by growing soft tissues separate the bones
from each other allowing for compensatory bone growth into the space.
according to Nanci what 2 things cuase bone increase in size (growth):
1) bone remodelling , long as more deposition than resorption
2) simultaneous relocation and displacement processes (like in mandible)
The mechanism for bone growth and development according to Lieberman:
1) drift
2) displacement
2b) secondary displacement
3) rotation
1) Equal bone deposition and resorption on opposing surfaces causes a bone to
move in space (→ Cobourne’s Relocation), e.g. downward drift of palate.
2) Displacement: Growth in one location causes the bone to be pushed away from
other structures;
2b) Secondary displacement: Relocation of bones that are not growing themselves;
e.g. displacement of the toes from the pelvis as the femur grows.
4) Rotation: Result of reversed depository and resorptive fields on either side of a
central axis (→ Combination of displacement and drift).
what mechanism is this:
Equal bone deposition and resorption on opposing surfaces causes a bone to
move in space (→ Cobourne’s Relocation),
2) give e.g.
drift
2) downward drift of palate
what mechanism is this:
Growth in one location causes the bone to be pushed away from
other structures;
2) give e.g.
1) displacement (primmary)
2) condyle growth
what mechanism is this:
Relocation of bones that are not growing themselves;;
2) give e.g.
secondary displacement
e.g. displacement of the toes from the pelvis as the femur grows.
out of these 2 which is endochondral ossification:
1) cranial base
2) cranial vault
3) facial bones
1
What causes cranial vault and cranial base flexion?
2) which facial feature doe this effect/
3) why?
1) expansion of the brain
2) occlusion
3) degree of flexion
4) influences
the growth of the naso-maxillary complex and mandibular condyle
What determines shape and final facial configuration ?
2) What other role des this tissue play in bone formation?
1) growth of soft tissues
2) molecular signals for bone formation comes from the growth of soft tissues.
What is the servosystem theory?
2) What does it think?
1) a theory on how occlusion is reached
2) growth of midface occurs via primmary cc (i.e. growth of maxilla). This is then sensed by dental occlusion effecting muscle function resulting in change in condylar growth. muscle function and condylar growth is also effected by hormonal facotrs (explains difference between men and women)
