An early stage of the primitive node (Prim. Node) of Hensen is indicated by a rearrangement of cells in the middle part of the germ disk. The node has not yet produced a noticeable localized elevation of the germ disk. Section 420.
Fig. 24. Heuser et al., 1945.
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Keywords: Hensen's node, germ disk, primitive node
Source: The Virtual Human Embryo.