[Notes on the embryology and anatomy of the diaphragm]

The main steps in the embryogenesis of the diaphragm are summarised, with particular reference to details of major importance in the formation of congenital hernias. Morphogenetic abnormalities of the diaphragm are described. Malformations occurring during the different stages of embryonal development (agenesia, total or partial aplasia or eventratio, restructuring defects) and their incidence are also illustrated. A personal view concerning the topography of congenital hernias of the diaphragm is expressed, with particular reference to those proceeding through incostant foramina.