Formation of the Greater Omentum

The dorsal mesentery of the stomach, or the dorsal mesogastrium, elongates considerably (not drawn to scale here), forming the greater omentum and its omental apron (Big red oval is stomach, smaller red circle is transverse colon, and green is kidney). As this apron lies doubled upon itself, its layers fuse together, obliterating the space that once was continuous with the lesser sac. Note how a portion of the dorsal mesogastrium fuses to the upper surface of the transverse mesocolon, as well.