Embryo No. 7802, stage 7, to show the primitive streak, which appears as a group of cells emerging from the ventral surface of the epiblastic plate. The wall of the umbilical vesicle is trilaminar. Section 44-1-2.
Fig. 7-11. O'Rahilly and Müller, 1987.
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Keywords: epiblastic plate, primitive streak, umbilical vesicle
Source: The Virtual Human Embryo.