On the intrauterine 26th day, an endodermal thickening appears in the ventral wall of the duodenum at the base of the hepatic diverticulum, budding toward the ventral mesentery
. This area called the cystic diverticulum will form the bile duct and cystic channel.
The occurrence of these peritoneal folds attributed to the abnormal predisposition of the ventral mesentery in the embryonic life.
As the development proceeds most of the ventral mesentery disappears except in the region of terminal part of the oesophagus, the stomach and the upper part of the duodenum and is derived from the septum transversum.
A ventral mesentery
only exists in the terminal part of the oesophagus, stomach and the proximal part of the duodenum.
At about the 28th day of intrauterine life, transiently, the dorsal and ventral mesenteries divide the peritoneal cavity into right and left halves, but the ventral mesentery
soon disappears, except around the liver and in front of the stomach.6,7
At this stage, a posterior rudiment can be clearly detected as a thickening growing anteriorly from the cloaca along the free margin of the ventral mesentery