Category Archives: Embryology


These images are from Ernst Haeckel’s 1874 The Evolution of Man shows comparisons between cross-sections of different animals and their embryos at different stages of development. For Haeckel the development of an embryo retraced the evolutionary history of the animal. The different colors represent the four types of tissues out of which all the organs formed.

(Image source). Ernst Haeckel. Anthropogenie, oder, Entwickelungsgeschichte des Menschen. Leipzig: W. Engelmann. 1874.

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Human embryonic cells

Human embryonic cells at various development stages: 4-cell, molura,blastocyst, and hatching blastocyst (Cover image from Cell-Research)

Image from cell-research

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Pigmentary Mosaicism

Hypopigmentation streaks in a linear pattern on the limbs is consistent with an enormous range of cytogenetic abnormalities. Blaschkolinear hypopigmentation (also called hypomelanosis of Ito) is typically linked to translocations of an X chromosome and an autosome, as in this case.

Image source NEJM (link)

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Spine of Human Embryo

The primitive spinal cord is flanked on either side by cartilaginous precursors of the vertebrae.

Image Source Medical School tumblr (link)  Image by Ed Uthman (flickr)

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