Growth and Development Flashcards
anatomic phenomenon
growth – change in size or nuber and largery anatomic phenom.
physiologic and behavioral phenomenon
development – increase in complexitey
concept 1
pattern –> patterns REPEAT and refers to COMPLEX SET OF PROPORTIONS
- these PROPORTIONS CAN CHANGE over time
LIKE AT BIRTH HEAD IS 50% of body but then at full growth may be like 25% or less of growth
scammon’s curves looks at what
- lymphoid
- neural
- general
- genital
patterns of growth in these areas represented by a % of adult size in relation to age
neural tissue growth?
complete by age 6-7 usually
lymphoid tissue growth?
grows beyond adult size and then involutes and puberty commences
concept # 2
explain
VARIABILITY
- patterns repeat reliably, but still everyone is different
*important to clinically differentiate individuals that ay be extremes of NORMAL variations, from those OUTSIDE this NORMAL range
concept #3
Timing
explain timing
same event happens for different individuals at different times
biologic clocks of different individuals are set differently
variations in timing aremost obvious in adolescence
because of this variability– chronologic age is often not a good indicator of growth status
chronological age good indicator of growth status?
NO – b/c of variability
craniofacial pattern change
see a clockwise end to growth a- e
a= cranial base (stops growing first)
then frontal then maxilla then mandible then ramus
growth pattern seen in neural tissue vs general
neural early jump then plateus
general - S shaped curve spike, plateu, and increase at puberty agian then plateus
T/F patterns repeat
TRUE - but variablity in these patterns
sign of alarm in standard growth charts - check up?
if child over 2 consectutive periods of time - like 2 checkups in a row child is falling or rising 2 percentile in change – sign of alarm
calander or clock good indicator for concept of timing?
NO - the SAME event happens at DIFFERENT TIMES for different people
chronological growth?
not a good indicator of timeline
craniometry growth study model
Pro
con?
pro= precise
only cross sectional – so person is not alive
Anthropometry growth study model
Pro
con?
pro- longitudinal
measuring external body
con- less precise on bony structures - like what is inside
cephalometric radiology growth study model
Pro
con?
pro = longitudinal possible, relatively precise
con- not all measurements possible
cone bean technology growth study model
Pro
con?
pro - low dose 3-D precidse
cons - expensive
can see a lot of structures
hand wrist radiography?
growth study model
- can capture when puberty should be starting and timing of it when looking at development or fusing of certain anatomical aspects of the hand
fully fused? – then height probably wont increase
increase in size independentof number or size of cells?
secrete extracellular material
hypertrophy
increase in size of cells
hyperplasia
increase in NUMBER of cells
interstitial growth
growth from WITHIN
a combination of hyperplasia and hypertrophy
characteristic of soft tissues and uncalcified cartilage
appositional growth
increase in sie by surface addition
mainly through extracellular secretions
characteristic of hard tissues (bone and teeth) and calcified cartilage
formation of cartilage
chondrogenesis
chondrogenesis details
- chondroblasts produce matrix
- cells are encased in matrix and become chondrocytes
- chondrocytes enlarge, divide, and produce more matrix
- matrix remains uncalcified
- a cell membrane covers the tissues but is not essential for further growth
intramembraneous bone foramtion
thisi type of bone is derived from neural crest cells due to mild tension forces
evidence of intramembraneous bone formatin?
first evidence is IN MANDIBLE at the 6th PRE-NATAL week and by the 8th week many centers of ossification can be seen throughout the head
this type of ossification occurs in the cranial vault and both jaws for further growth
growth occuring a lot in the cranial vault and the jaws?
intramembraneous bone formation
membrane more important in what type of growth?
INTRAMEMBRANEOUS GROWTH AND
INTRAMEMBRANEOUS BONE FORMATION STEPS
- osteoblasts produce osteoid
- cells and blood vessels are encased in osteoid and become osteocytes
- osteoid is produced by membrane cells - osteocytes are not longer contributing to growth
- osteoid calcifies
- a cell Membrane – PERIOSTEUM covers the bone and i ESSENTIAL for further growth
osteoid produced by?
membrane cells
what is essential for further intramembraneous bone formatino?
periosteum (cell membrane ) covering the bone
- SAME FOR ENDOCHONDRLA – once osteoid calcifies the periosteum covers and is essential for further growth as well
bone forming from cartilage is termed
endochondral bone formation
endochondral bone formation occurs when
starts to occur as early as the 8th PRENATAL WEEK
only the bones of the cranial base and portions of the calvarium are derived from this method
from endochondal bone formation?
only the bones of the cranial base and portions of the calvarium are derived from this method
difference in quality of endochondrla vs intramembraneous once formed?
no
steps in endochondral bone formation
- hypertrophy of chondrocytes and matrix calcifies
- blood vessels and connective tissue invade
- osteoblasts differentiate into osteoid
- osteoid calcifieis
- cell membrane – periosteum covers the bone and is essential for further growth
bone vs cartilage with rigidity
bone - rigid
cartilage – flexible
bone vs cartilage with calcificationo
bone - calcified
cartilage - uncalcified
bone vs cartilage with vascularity
bone- vascular
cartilage - avascular
bone vs cartilage with membrane
bone - ESSENTIAL
cartilage – non- essential
bone vs cartilage with resistence
bone - pressure SENSTITIVE
cartilage – pressure TOLERANT (think because it is more flexible - more tolerant to pressure and resistiance )
implication of bone being sensitivie to pressure
like tongue sucking and implications on bone movement in the oral cavity
growth in the cranial vault by
intramembraneous growth
with remodeling occurs primarily at periosteum lined surfaces called sutures – and at inner and outer surfaces
growth of cranial base
feature of this
endochondral growth
as the ossification continues – bands of cartilage remain between bones – called synchondroses
premature fusoin of all sutures will show? - general
downward grwoth and bulging of eyes as the brain and tissue need to continue to develop and if sutures closed – will take path of least resistance
craniosynostosis
pre-mature fusion of sutures
pre-mature fusion of sutures termed
craniosynostosis
coronal suture prematurely closes?
brachycephalic – short front to back , wide left to right
sagittal suture prematurely closes?
dolichocephalic – long front to back, narrow left to right
coronal and sagittal suture prematurely closes?
oxycephalic - long vertical , with short and narrow head
metopic suture prematurely closes?
trigonocephaly – triangular shaped head
allsuture prematurely closes?
microcephaly – small cranium
any unilateral suture prematurely closes?
plagiocephaly – unilateral decrease on fused side and increase on other
important synchondroses and age
inter-sphenal – fuse by age 6
spheno-ethmoidal – fuse by age 6
spheno-occipital – remains active until after puberty
inter-sphenal synchondroses
fuse by 6
Anterior portion of the cranial base - relaibel structure not changing over time – good landmark to compare over time
Determine or predict growth
same with spheno-ethmoidal
growth of maxilla
develops postnatally entirely by INTRAMEMBRANEOUS OSSIFICATION
DOWN AND FORWARD
growth occurs in 2 ways
- apposition of bone at cranial sutures
- surface remodeling on the anterior and palatal regions
where there is direction of growth -and displacement there is resorption and apposition
growth of the mandible
1/ intramembraneous growth accounts for the main body of the mandible
endochondral growth is important at the CONDYLE
condyle growth?
endochondral growth is important here
theories of growth
- bone is the primary determinant of its growth
- cartilage is the primary determinant of skeletal growth , while bone responds
- soft tissue matrix is the primary determinant of growth and both bone and cartilage respond to its growth
growth site vs center
site: A location at which growth occurs
center– a location at which independent, genetically controlled growth occurs
all centers are ___ but not all ___ are ___
all centers are sites but not all sites are centers
sites – occur in that area only but if remove center and place somewhere else can still grow??
bone as a determinant?..
- growth occurs at the sutures and along the periosteum covered surface
- cranial base is example of this - this growth is REACTIVE to surrounding changes
- tension enhances growth - stimukate apposition
- pressure impedes growth
- BONE IS NOT a primary growth center
cartilage as a determinant of growth
cartilage grows in many bones, and then gets replaced by bone
only certain cartilage areas serve as growth centers
- epiphyseal cartilage of long bones
2. cranial base synchondroses
3. nasal septum
soft tissue as a determinant?
theorized by dr. moss in 1960’s
grants epiphysieal cartilage of long bones as growth center, but not cartilage in the head
growth of the face occurs as a response to functinal needs and neurotrophic influences, mediated by the soft tissues
functional matrix theory
functinal determinant of heaf growth
- expanding brain leads to forces on the calvarium, and leads to its growth
major reason for growth of maxilla and mandible is the enlargment of nasal and oral cavities iin respones to functional needs
___ as a functinal matrix
brain
brain as a functinal matrix
- brain expands with growth
- pressure on the surrounding bones
- tension at the sutures between the bones
- grwoth to accomodate the brain growth
*the sutures allow displacement of vault bones and fossa configuration necessitates drift
