Diaphragmatic hernia.

Congenital Hernia The development of the diaphragm is complicated (Fig. i). The anterior portion is formed from the septum transversum. The septum transversum originally arises in the upper part of the cervical region, and in the course of its caudal migration it receives its innervation from branches of the 3rd, 4th and sth cervical nerve roots (the phrenic nerve) which accompanies it in its descent. In the 17 mm. embryo, the septum transversum has reached its permanent position. The posterior part of the diaphragm is formed by the fusion of the pleuro-peritoneal membrane and the dorsal mesentery. The pleuro-peritoneal membrane is the last structure to complete the formation of the diaphragm. This takes place earlier on the right side, at about the 17 to i8 mm.