Tags: Anatomical Structure, Embryology.
Heuser’s membrane (or the exocoelomic membrane) is a short lived combination of hypoblast cells and extracellular matrix.At day 9-10 of embryonic development cells from the hypoblast begin to migrate to the aembryonic pole forming a layer of cells just beneath the cytotrophoblast called Heuser’s Membrane. It surrounds the exocoelomic cavity (primitive yolk sac) i.e. it lines the inner surface of the cytotrophoblast.