Anterior-posterior and lateral folding form the primitive gut
ÿEmbryonic disc grows faster in length than the yolk sac causing the embryo to bend.
lDorsal surface grows more rapidly than the ventral
ÿLateral folding
lFusion with apposing side except in the region of the yolk sac, and allantois
ÿFolding brings the heart and septum transversum caudal to bucco-pharyngeal membrane.