skull-intro and organization

Question 1

what general bones are formed endochondrally

Answer 1

basicranium + small bones (neck, styloid, middle ear)

Question 2

bones with dual ossification paths

Answer 2

sphenoid, temporal, occipital

Question 3

two primordia of skull bones

Answer 3

ectomesenchyme (neural crest derived) or paraxial mesoderm

Question 4

which bones develop from paraxial mesoderm

Answer 4

parietal, occipital, petrous temporal, area posterior to sella turcica of sphenoid

Question 5

bones of the face develop from ___

Answer 5

ectomesenchyme

Question 6

craniosynostosis. how does it relate to primordia?

Answer 6

premature fusion of cranial sutures. Often happens at jxn of ectomesenchyme/paraxial mesoderm (frontal/parietal) due to lack of signaling

Question 7

chordoma: what is it? where?

Answer 7

neoplasm of persistent notochord. usually at skull base (sella trucica, meeting of different precursors) or sacrum