Growth and Development of the Human Skeleton Flashcards
give an overview of bone development
- begins as cartilaginous analage
- periosteum forms
- primary ossification centre forms and ossification begins
- primitive joint begins to develop
- more blood supply forms alongside secondary ossification centre
- growth plate eventually disappears, bone and cartilage left
what layer is bone derived from
mesoderm
when to limb buds begin to develop
week 4
what layers are the limb buds made of
mesoderm covered with ectoderm
in limb development what forms the (a) bone (b) muscle
(a) lateral mesoderm (b) somatic mesoderm
what is the apical ectodermal ridge important in
ensuring proper limb development
what gene controls the apical ectodermal ridge
sonic hedgehog gene
what can go wrong during skeletal development
failure of formation or separation, hypo/hyperplasia, duplication, constriction ring syndromes, skeletal dysplasia
what are constriction ring syndromes
abnormal tissue forms around growing limbs
what are cartilaginous analages
small areas of cartilage
by when are primary ossification centres in all long bones
12 weeks
where and when do secondary ossification centres first appear
distal femur at 36 weeks
describe the zones of the growth plate and what occurs in each
- zone of reserved cartilage
- zone of proliferating cartilage (proliferation begins)
- zone of hypertrophic cartilage (becomes swollen)
- zone of calcified matrix (bone)
where can appositional growth of bone occur
through the perichondrium and perichondrial ring
what is the Heuter-Volkmann Law
distraction across the plate increases growth whereas compression suppresses growth
what, besides the Heuter-Volkmann Law, stimulates the growth plate
increased blood flow, fractures, releasing periosteum
what methods can be used to predict growth
height on 2nd birthday x2
menelaus - after age 10 grow 10mm from distal femoral plate and 6mm from proximal tibial plate each year
bone age
Paley multiplier
what percentage of femur growth comes from the (a) proximal plate (b) distal plate
(a) 30% (b) 70%
what percentage of tibial growth comes from the (a) proximal plate (b) distal plate
(a) 60% (b) 40%
what is used to calculate bone age
x-ray of L wrist
what can the menelaus method be used for
to calculate how much growth is left and when to stop for treatments, etc
when does the spine grow until
late teens
why is menarche useful in spinal growth
signals 18 months until end of spinal growth
what is the Risser score
check iliac apophysis on x-ray, this shows the degree of ossification and the spinal maturity left
