Carnegie Stage 9 |
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| N17 | N17 | N17 | N509 | |||
| 46 XY | 46 XY | 46 XY | 46 XY |
Age is approximately 26 postovulatory days Length is approximately 1.4 - 2.5mm External Features Include: the head fold is present. Neural folds may be apposed but are not yet fused at any point. No visible pharyngeal arch. This is the first stage that somites appear. O'Rahilly R and Muller F [1987] Developmental Stages in Human Embryos. Carnegie Institute, Washington, Publication no. 637, and O'Rahilly R, Müller F (2010) Developmental stages in human embryos: revised and new measurements. Cells Tissues Organs. 192:73-84. PMID: 20185898. |