Ortho Final Flashcards
(24 cards)
What are the components of the viscerocranium?
Maxilla, alveolar process, corpus (body) and ramus
What are the components of the neurocranium?
cranial base
What is the gonial angle?
Angle of the mandible
Is growth an anatomical or a physiological/behavioral?
Growth (an increase in size) is anatomical where as development is physiological
When is the brain 98% done? 91% done? 63% done?
98%= 15 yrs 91%= 5 yrs 63%= birth
Compare the changes in the proportions of the neurocraniam:face during growth at
1) Birth
2) 2 years
3) 5 years
4) Adults
1) Birth = 8:1
2) 2 years =6:1
3) 5 years = 4:1
4) Adults = 2:1
At birth the face is small and the neurocranium well developed
MX or MN grow first?
MX bc closer to neurocranium
What is the term used to describe the increase in the face relative to the neurocranium
Cephlo-caudal growth
–describes the general growth pattern of organisms to develop areas near the main neural area (typically the head) earlier than areas of the body that are more distant.
What is the calvaria?
What are the bones?
How does it ossify?
bones of the skull cap or the roof of the neurocranium *
- *via intramembranous calcification depending on presence of brain**
- Occipita
- Parietal bones (2)
- Temporal bones (2)
- reater wings of the sphenoid bone
- Frontal bones (2)
anencephaly
NO calvaria form
*exception! squamous temporal bone
What are the sutures of the calvaria?
Metopic suture
Coronal suture
Lambdoid suture
Sagittal suture
craniosynostosis? What happens when this happens?
premature fusion of the cranial sutures
- There is the cessation or the distortion of the cranial growth resulting in abnormal skull shape, elevation of the intracranial pressure, blindness, mental retardation and facial asymmetry
- Crouzon, Pfeiffer, Boston types
- only 1:2000 LIVE births
resynostosis
rapid re-growth is called re-synostosis and occurs in up to 40% of patients who undergo cranial vault reconstruction
*** Basically what it is saying is this. You have a synostosis, you relieve it and then you face re-synostosis
What are the bones of the naso-maxillary complex?
There are 5
** maxilla, the palate, the zygomatic arch, the orbit, and the nose
What % of the maxillary displacement is due to passive displacement by the cranial base? Important when?
1/3 of the movement of the maxilla can be attributed to passive displacement
** important in the earlier years, especially for primary dentition but less important as growth at the synchondroses slows with the completion of neural growth at age 7
What are the five theories to know? And their respective years?
RSCFS - real surgeons can fail sometimes
1) Remodeling theory - 19030s
2) Sutural theory - 1940s
3) Cartilage + Nasal septum theory - 1950s
4) Functional matrix theory - 1960s
5) Servosystem theory
growth is influenced by?
1) genetic factors (the most important factor)
2) environmental factors
- nutrition
- degree of physical activity
- illness
- trauma
what is the role and difference between growth theories?
They attempt to explain the determinants of craniofacial growth
** differs in LOCATION at which genetic CONTROL is expressed
remodeling theory
- craniofacial growth occurs ONLY by the selective addition and resorption of bone on the surfaces
- jaw growth is going to be characterized by the deposition of BONE ONLYon the posterior surface of the maxilla and mandible
- Calvarial growth is going to be characterized by the deposition of bone on the ectocranial surface (outside) where as the resorption happens intracranially or endocranially
- SUTURES AND CARTILAGE HAVE little OR no ROLE IN CRANIOFACIAL GROWTH
sutural theory
Weinmann and Sicher in the 1940s
- sutures are considered as growth centers and location where it is intrinsically regulated and primary growth occurs
- Growth of the cranial vault is caused by the intrinsic pattern of expansive proliferative growth by sutural connective tissue that forces the bones of the vault apart = NOT SELECTIVE
- Proliferation of the sutural connective tissue in the cirfcummaxilalry suture system surrounding the maxillary skeletal complex will force the midface to grow downward and forward
cartilage + nasal septum theory
James H Scott in 1950
- It says the cartilage is the determinant of craniofacial growth
- The condyle is the growth center and the pace maker of the jaw
- The nasal septum is the pace maker for other aspects of maxillary growth
*The epiphyseal cartilages and the cranial base are the independent growth centers and the nasal septum kinda does
functional matrix theory
Melvin Moss in 1960s
* hereditary and genes play no significant deterministic role in the growth of the craniofacial skeletal except initially
- craniofacial skeleton grows in direct response to its EXTRINSIC and epigenetic environment
- two types of functional matrices: Periosteal matrix and the capsular matrix
- The craniofacial skeleton does not grow in a primary faction that allows the brain, the eyes, etc to fill into the skeleton. Instead, what happens, is that the skeleton grows secondarily to compensate for the growth of the functional matrix and in particular, the growth of related expansion of the capsular matrices
servosystem theory
Alex Petrovic in 1970s–
his is a theory that says the entire cycle is continuously activated as long as the midface-upper dental arch continues to grow and mature and you need the extrinsic, hormonal and functional factors that remain supportive
- midface grows downward and forward under influence of the cartilaginous cranial base and nasal septum and this is influenced by the intrinsic cell tissue related properties that is seen in all primary cartilages and extrinsically by the endocrine system
- MX grows first causing a discrepancy that activate muscles resposible for MN protrusion and indirectly though vascular supply to TMJ
primary vs secondary cartilage are growth site/center
Primary cartilge is the growth center
2ondary cartliage is the growth site
