of closure of the pleuro-peritoneal canal
Development of the diaphragmatic primordium (3-4 weeks).
At the end of this phase the primitive diaphragm is composed of two parts:
1. Ventral transverse septum
2. Dorsal diaphragmatic mesentery
of the pleural cavity and closure of the pleuro-peritoneal canals
(4 to 8 weeks)
The diaphragm is formed from the septum transversum and the dorsal mesentery, which separate the thoracic system from the abdominal organs. The poster-olateral areas are the last to close and the left side closure occurs later than the right.
concept of development (Iritani, 1984)
Primitive diaphragm consisted of 3 parts:
1. Transverse septum ventrally
2. Pleuroperitoneal canals caudally
3. Posthepatic mesenchymal plate (interposed), leads to the closure of the canals.
Migration of intraperitoneal structures in the hemithorax leads to compression and secondary pulmonary hypoplasia.
Relative left ventricular hypoplasia
Right to left shunt through foramen ovale or ductus arteriosus