Keywords: 
cerebral vesicle (telencephalon), 
diencephalon, 
isthmus, 
lens vesicle, 
mamillary region, 
mesencephalon (midbrain), 
metencephalon, 
myelencephalon, 
optic cup, 
pons region (metencephalon), 
pontine flexure region, 
roof of rhombencoel (fourth ventricle) (collapsed), 
telencephalon
Source: The Virtual Human Embryo.