Skip Navigation
Stage 1 / 1 day Stage 2 / 2-3 days Stage 3-1 / 4 days Stage 3-2 / 4-5 days Stage 4 / 6 days Stage 5a-1 / 7 days Stage 5a-2 / 8 days Stage 5b / 9 days Stage 5c / 12 days Stage 6 / 13-17 days Stage 7 / 16-19 days Stage 8 / 23 days Stage 9 / 25 days Stage 10 / 28 days Stage 11 / 29 days Stage 12 / 30 days Stage 13 / 32 days Stage 14 / 33 days Stage 15 / 36 days Stage 16 / 39 days Stage 17 / 41 days Stage 18 / 44 days Stage 19 / 45-47 days Stage 20 / 49 days Stage 21 / 49-52 days Stage 22 / 52-55 days Stage 23 / 56 days
Atlas of Human Embryos Chapter   Figure

cephalic flexure, cervical flexure, diencephalon, hypothalamus, isthmus, lamina terminalis, mamillary area, mesencephalon, metencephalon: pons area and rhombic lip (cerebellum), myelencephalon (medulla oblongata), neurohypophyseal bud, optic stalk and chiasma area, pineal bud area, pontine flexure, preoptic area, primitive filum terminale, primordial olfactory bulb, primordial piriform cortex, roof of rhombencoel (fourth ventricle), spinal cord, telencephalon (cerebral vesicle)

Central nervous system of the 18-mm embryo. Arrows indicate the position of the cephalic, pontine and cervical flexures.


Keywords: cephalic flexure, cervical flexure, diencephalon, hypothalamus, isthmus, lamina terminalis, mamillary area, mesencephalon, metencephalon: pons area and rhombic lip (cerebellum), myelencephalon (medulla oblongata), neurohypophyseal bud, optic stalk and chiasma area, pineal bud area, pontine flexure, preoptic area, primitive filum terminale, primordial olfactory bulb, primordial piriform cortex, roof of rhombencoel (fourth ventricle), spinal cord, telencephalon (cerebral vesicle)

Source: Atlas of Human Embryos.