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The Endowment for Human Development
The Endowment for Human Development
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Slideshow: Favorites

Touching Thumbs

#175, Slide 57 of 74

3 months

From The Biology of Prenatal Development.Buy Now

Note:

One reason the thumb is unique among the fingers is the presence of only one joint instead of two.

Label Key:

1. nail field
2. right thumb
3. vein
All ages referenced to fertilization, not last menstrual period. One month = 4 weeks.
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