Central nervous system of the 5-mm embryo. Arrows indicate the position of the cephalic and cervical flexures.
Keywords: cephalic flexure, cervical flexure, chiasmal area, diencephalon, lamina terminalis, mesencephalon (midbrain), neurohypophysial bud area, optic stalk (CN II), optic vesicle, pre-optic area, primitive filum terminale, prosencephalon (forebrain), rhombencephalon (hindbrain), rhombomeres, roof of rhombencoel (fourth ventricle), spinal cord, telencephalon
Source: Atlas of Human Embryos.