Assertion: arachnoid | /r/CapableOf | develop within undifferentiated mesenchyme
Facets:
value: in human embryos
type: LOCATION
Source sentences:
text: In human embryos the pia mater, arachnoid, and dura mater develop within the undifferentiated mesenchyme that fills the space between the periphery of the neural tube and the inner wall of the vertebral canal.