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Slideshow: Slideshow 1

The 4-Week Embryo

#368, Slide 6 of 19

3 weeks, 4 days

From The Biology of Prenatal Development.Buy Now

Label Key:

1. brain
2. body cavities
3. somites
4. tail
All ages referenced to fertilization, not last menstrual period.
Fertilization BeginsThree-Cell EmbryoEarly BlastocystImplantation Well UnderwayThe 4-Week EmbryoVitelline Vessels and Yolk SacHand Plate and Vital OrgansHand, 7 Weeks Pregnant7½-Week EmbryoRight Eye and Facial Profile9-Week Fetus, MRI AnimationExit Stage LeftPosterior Surface of Left ThighStill HidingThe MouthFace, 27-Week FetusFace and Left ForearmReady for Birth and Beyond
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