Craniofacial growth Flashcards
(45 cards)
Describe the size of the head related to the body at:
- 2 months IU
- at birth
- adult male
- 2m IU = half of body size
- birth = 1/4 body side
- adult male - 1/8 body size
What is the curve that demonstrates postnatal growth
Scammon’s growth curve
What does Scammon’s growth curve show us about the growth of the maxilla and the mandible?
- Maxilla is close to the cranium and is influence by earlier growth in this region (therefore it grows before the mandible)
- Mandible follows general body growth therefore it grows later on
What are the examples of growth curves that can be plotted
- distance curves (cumulative graph of heigh vs age)
- Velocity curves (incremental graph of change in height vs age)
What is ossification
Process by which new mineralised bone is formed
What are the two ways ossification occurs in the craniofacial complex
Endochondral
Intramembranous
What is endochondral growth
Bones are formed via replacement of the cartilage, which is seen at epiphyseal plates of the long bones and the synchondroses of the cranial base
What are synchondroses?
Cartilaginous joint that act as growth centres
What do the synchondroses make up?
The ethmoid, sphenoid and basioccipital bones (thus the cranial base)
Describe what happens with growth at the synchondroses
Bones either side of the synchondroses move apart thus lengthening the cranial base
List the synchondroses
Interspehnoidal
Spehno-ethmoidal
Spehno-occipital
What is intramembranous growth
Bone is laid down and resorbed by investing periosteum and endosteum (bone remodelling)
Describe how intramembranous growth occurs
Periosteal activity at the surfaces of the bone and remodelling and growth at periosteal lined contact areas (called sutures)
What is the role of sutures in CFC growth
Bones of the skull and face articulate at sutures and the growth occurs along the sutures
Which bones are formed via intramembranous growth
Cranial vault
Facial bones
Mandible
Maxilla
What is the importance of the speno-occopital synchondrosis
Growth at the SOS influences the overall facial skeletal pattern as it increases the length of the cranial base
How does SOS growth of the cranial base affect occlusion
The mandible and maxilla are connected to the cranial base
Describe cranial base relationship with skeletal pattern
- Long cranial base associated with class II
- Short cranial base angle associated with class III
What are the two theories for control of facial growth
1) Tight genetic control that has no influence of environmental factors
2) Controlled loosely by genetics and takes place in response to growth of surrounding tissues
what is the evidence of genetics as a role in facial growth?
Families tend to have similar facial growth
What is the general pattern of facial growth as you age
Rapid in early years then slows in prepubertal period
Rapid during puberty then slows down until adult levels reached
When does puberty roughly occur?
12 in girls
14 in boys
How does growth of the cranial vault (calvarium) occur
- Combination of drift and displacement
How does drift occur in cranial vault growth
Resorption of intracranial aspects of bone, whilst bone is laid down on external surfaces
