• Humio Mizoguti
Part of the Advances in Anatomy, Embryology and Cell Biology book series (ADVSANAT, volume 116)


The morphological features of a well-preserved human embryo having 15 pairs of somites are described and illustrated with a complete set of photomicrographs. This embryo was found during a forensic dissection of a Japanese woman, fixed in 10% formalin for 5 days, and embedded in an epoxy resin mixture according to routine procedures. Serial sections about 0.75µm thick were made and stained with toluidine blue. The most important features were as follows:
  1. 1.

    The embryo measured 4.1 mm in greatest length and was quite symmetrical viewed dorsally.

  2. 2.

    Closure of the neural tube took place from the level of the first branchial groove, corresponding to the level of the anterior one-third of the rhombencephalon, to that of about 0.4 mm posterior to the 15th somite, coming across the anterior end of the cloacal membrane. The neural plate and the wall of the neural tube consisted exclusively of a pseudostratified columnar epithelium, and neither the mantle nor marginal layers were identified anywhere.

  3. 3.

    At the anterior end of the embryo there was a conspicuous optic evagination, and at the dorsal end of the second branchial groove a round otic placode.



Neural Tube Neural Plate Marginal Layer Cloacal Membrane Intermediate Mesoderm 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1989

Authors and Affiliations

  • Humio Mizoguti
    • 1
  1. 1.Department of AnatomyKobe University School of Medicine650 Chuoku, KobeJapan

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