![](/drem/stage21/labels2/S45L.gif)
![alar plate of metencephalon (cerebellum), artifact fracture(s), commissure in roof plate of mesencephalon, intermediate zone, isthmus of rhombencephalon, marginal zone, osteogenic layer, rhombencoel (fourth ventricle), subarachnoid space, trochlear nerve (CN IV), ventricular zone](/drem/stage21/Z0/S45N.jpg)
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Carnegie Embryo #4090 | Location: 3-9
Keywords: alar plate of metencephalon (cerebellum), artifact fracture(s), commissure in roof plate of mesencephalon, intermediate zone, isthmus of rhombencephalon, marginal zone, osteogenic layer, rhombencoel (fourth ventricle), subarachnoid space, trochlear nerve (CN IV), ventricular zone
Source: The Virtual Human Embryo.