Bassett Collection of Stereoscopic Images of Human Anatomy

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Embryo, placenta and fetal membranes

Two-month-old embryo within amniotic sac

Image #164-5

KEYWORDS: Peripheral nervous system.

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Higher resolution images are available for a fee. Contact Drew Bourn, PhD, MLIS.

Embryo, placenta and fetal membranes

Two-month-old embryo within amniotic sac

The chorion of this fresh surgical specimen has been opened to expose the amniotic sac (1) and yolk sac (3), both of which have been displaced to reveal the fetal surface of the placenta (9). The yolk sac remains attached to the umbilical cord by a slender stalk containing blood vessels which are visible in the photograph.

1 .	Amniotic sac (enclosing fetus within amniotic fluid)
2 .	Umbilical arteries (distinguished by thicker, white walls and smaller lumen than those of umbilical vein)
3 .	Yolk sac
4 .	Yolk stalk (note vitelline artery within stalk)
5 .	Cut edge of chorion
6 .	Umbilical cord (note spiraling course of umbilical arteries within cord)
7 .	Umbilical vein
8 .	Chorionic VIII
9 .	Placenta