MSK Pt 1 Flashcards
The skeleton is composed of? (2 tissues, 3 cell types)
bone/cartilage
osteoblasts/osteoclasts/chrondrocytes
Skeletal tissue is derived from three embryonic cell lineages. What are they?
cranial neural crest cells (head)
paracial mesoderm cells/somites (axial skel)
lateral plate mesoderm (limbs)
Limb buds begin to develop during the _____ week.
4th
What are the 4 steps of skeletogenesis?
patterning
organogenesis
growth
homeostasis
When can we see limb buds?
7th week (I’m pretty sure in OB we learned wk 9 buuuuuut what else is new)
What can we see during the 9-11th week?
clavicle + mandible
When do we see hands and feet?
12-14wks
When do we see the distal femoral epiphysis? The proximal tibial epiphysis?
29-34wks
35wks
How is the femur length measured?
b/w the distal and proximal ossification centres of the femoral diaphysis
The cardio-thoracic circumference ratio increases through gestation, but should not measure more than ______. What can it indicate if the ratio is increased?
0.5
cardiac- fetal cardiomegaly
thoracic- pulmonary hypoplasia
Thoracic/abdominal circumference should measure _____ after 20 weeks.
> 0.8
Skeletal dysplasia aka
dwarfism
umbrella term for conditions affecting bone and cartilage growth
The most common severe skeletal dysplasias manifest with:
severe micromelia (shortening of all limbs) and thoracic dysplasia
Most common types of skeletal dysplasias can be detected by what?
FL
if it’s 1-4mm below 2 SD points, more measurements are required.
If it’s 5mm below 2 SD points, there’s a high likelihood of SD
What helps distinguish skeletal dysplasia from severe IUGR?
femur length to foot length ratio
*foot length is not affected with most SD so the ratio is decreases