Ventral abdominal wall

The ventral abdominal wall develops in connection with the caudal flexion. A transverse section through the caudal part of the embryonic body shows that the peritoneal cavity in this region is already closed to the outside. The ventral body wall contains the connecting stalk including the allantois and the umbilical vessels. The hindgut lies in the peritoneal cavity. It is covered with visceral mesoderm, which merges into parietal mesoderm at the dorsal abdominal wall through the mesenterium. Ventrally, the right and left halves of the peritoneal cavity are in direct contact with each other. Contrary to what is sometimes asssumed, there is no ventral mesenterium.