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Stage 20 embryos have a greatest length of 18 to 22 mm and an estimated post-fertilization age of approximately 49 days. At this stage the upper limb is longer and slightly bent at the elbow. The hands are still far apart and the fingers are short, stubby and slightly curved over the cardiac prominence. The interorbital groove is conspicuous.


New structures include anterior communicating artery, biceps brachii muscle, dens of axis (C-2), medial accessory olivary nucleus, oculomotor nucleus, popliteal artery, quadriceps femoris muscle.

Section 245

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Mid-section of the eye

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