Stage 3 embryo in vitro showing collapse. The blastocystic cavity (blastocoele) is partially collapsed. The morphology of the inner cell mass (embryoblast) and trophoblast are unchanged. Collapse occurs frequently in in vitro blastocysts.
From: Veeck and Zaninovic´, 2003. Reproduced with permission of the publisher, Francis and Taylor Group.
Source: The Virtual Human Embryo.