![](/drem/stage21/labels/S13L.gif)
![artifact fracture(s), artifact space(s), cerebral aqueduct (mesocoele), missing tissue, osteogenic layer, subarachnoid space, surface ectoderm, vascular plexus](/drem/stage21/Z0/S13N.jpg)
![](/drem/rulerbg.png)
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Carnegie Embryo #4090 | Location: 1-13
Keywords: artifact fracture(s), artifact space(s), cerebral aqueduct (mesocoele), missing tissue, osteogenic layer, subarachnoid space, surface ectoderm, vascular plexus
Source: The Virtual Human Embryo.