Carnegie Stage 20 (50 post-ovulatory days)
Most embryos at stage 20 are approximately 50-51 postovulatory days old and measure 21-23 mm in length. Distinguishing criteria for this stage include upper limbs slightly bent at the elbows, short stubby fingers, hands curving over the cardiac region but still far apart from each other, and a fringe-like vascular plexus that marks growth centers laterally in the superficial tissues of the head.
Although some of the photographs below show abnormal embryos, the animations and MRI slice images all depict normal embryos. Abnormal embryos are noted in the titles of the large photos when they are opened.