CTB45 Principles of facial and bone growth

Question 1

What does growth mean?

2) What does development mean?
3) What are the 3 main stages of ontogenesis?

Answer 1

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

Question 2

What age does neural growth finish?

Answer 2

8 yrs

Question 3

Which grows faster maxilla or mandible?

Answer 3

maxilla growth is faster

Question 4

true or false

bones grow by simple symmetrical enlargement

Answer 4

false

Question 5

The mandible grows by elongation of ____a___ and ___b___ in a posterior and
superior direction; and the ____c___ lengthens.

Answer 5

a) b) condyle and ramus

c) body of the mandible

Question 6

What bones part of the neurocranium are part of chondrocranium?
2) what type of ossificaiton?

Answer 6

occipital, sphenoid, ethmoid, petrous and mastoid part of temporal
2) endochondral

Question 7

What bones part of the neurocranium are part of membranous neurocranium?
2) What type of ossificaiton

Answer 7

1) interparietal part of occipital, parietal, frontal, squamous part of temporal
2) intramembranous

Question 8

What type of offisification:

occipital, sphenoid,

Answer 8

endochondral

Question 9

What type of offisification:

ethmoid, petrous and mastoid part of temporal

Answer 9

endochondral

Question 10

What type of offisification:

squamous part of temporal

Answer 10

intramembranous

Question 11

What type of offisification:

interparietal part of occipital, parietal, frontal,

Answer 11

intramembranous

Question 12

what type of ossification:

vomer, palatine, zygomatic, mandible,

Answer 12

intramembranous

Question 13

how do they form:

1) meckel’s cartilage
2) malleus
3) incus

Answer 13

1)2)3) endochnodral ossifcaiton (as all part of pharyngeal arch 1

Question 14

What is formed from pharyngeal arch 1:

Answer 14

1) meckel’s cartilage
2) malleus
3) incus

Question 15

What is formed from pharyngeal arch 2:

Answer 15

1) Reichert’s cartilage
2) stape
3) styloid process

Question 16

how do they form:

1) Reichert’s cartilage
2) stape
3) styloid process

Answer 16

1)2)3) endochnodral ossifcaiton (as all part of pharyngeal arch 2

Question 17

intra or endochon:

1) -supraoccipital
2) interparietal bone of occipital
3) exoccipital
4) basioccipital

Answer 17

1) enchon
2) intramembranous
3) enchon
4) enchon

Question 18

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

Answer 18

1) 2)3) endo

4) intramembran

Question 19

what type ossification forms

a) epiphyseal cc
b) condylar cc
2) describe position of cells

Answer 19

1) a) endo
b) intra
2) a) aligned in columns
b) random (as multidirectional growth)

Question 20

what is formed in epiphyseal cc, and by what?

Answer 20

Hyaline cartilage formed by chondrocyte

proliferation, maturation, hypertrophy;

Question 21

Condylar cartilage:
\_\_\_A\_\_\_  zone is continuous
with mandibular periosteum.
\_\_\_b\_\_\_ cells respond to functional
loading and proliferate and differentiate to
form \_\_\_\_c\_\_\_

Answer 21

a) Fibrous articular
b) Mesenchymal
c) chondrocytes

Question 22

difference between bone relocation and bone displacement

Answer 22

1. Relocation: Bone deposition and resorption on opposing surfaces causes a bone to
   move (“drift”) in space (→ towards the side of deposition).
2. Displacement: External forces generated by growing soft tissues separate the bones
   from each other allowing for compensatory bone growth into the space.

Question 23

according to Nanci what 2 things cuase bone increase in size (growth):

Answer 23

1) bone remodelling , long as more deposition than resorption
2) simultaneous relocation and displacement processes (like in mandible)

Question 24

The mechanism for bone growth and development according to Lieberman:

1) drift
2) displacement
2b) secondary displacement
3) rotation

Answer 24

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).

Question 25

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.

Answer 25

drift

2) downward drift of palate

Question 26

what mechanism is this:
Growth in one location causes the bone to be pushed away from
other structures;
2) give e.g.

Answer 26

1) displacement (primmary)

2) condyle growth

Question 27

what mechanism is this:
Relocation of bones that are not growing themselves;;
2) give e.g.

Answer 27

secondary displacement

e.g. displacement of the toes from the pelvis as the femur grows.

Question 28

out of these 2 which is endochondral ossification:

1) cranial base
2) cranial vault
3) facial bones

Answer 28

1

Question 29

What causes cranial vault and cranial base flexion?

2) which facial feature doe this effect/
3) why?

Answer 29

1) expansion of the brain
2) occlusion
3) degree of flexion
4) influences
the growth of the naso-maxillary complex and mandibular condyle

Question 30

What determines shape and final facial configuration ?

2) What other role des this tissue play in bone formation?

Answer 30

1) growth of soft tissues

2) molecular signals for bone formation comes from the growth of soft tissues.

Question 31

What is the servosystem theory?

2) What does it think?

Answer 31

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)