[Phylogenetic interpretation of aortic arches and outflow tract partitioning]

The great thoracic and cervical vessels come from the complex metameric system, formed of the dorsal and ventral aortas and aortic arches. From the branchial respiratory system of fish to the mammalian configuration, numerous changes have occurred in parallel with the evolution of cardiac septation, which imposes constraints on the vascular system. In addition, an important cell population is involved with the partioning of the arterial bulb: the cardiac neural crests originating from the head. The examination of abnormalities of arterial bulb septation, considered as neurocristopathies, within certain limitations, demonstrates an association of abnormal features with ancestral configurations. Some aortic arch malformations can be considered as a continuation of ancient embryonic transient vessels, which should have disappeared. Exemplative malformations, such as the "tetralogy of Fallot", are similar to reptilian configuration of great vessels, associated with incomplete partition of both ventricles with an absence of sub-endocardial cushions. However, the presence in reptiles of two systemic arches and a pulmonary artery (in fact, 3 vessels arising from the arterial bulb) has no malformative equivalent in mammals. Arteria lusoria, double aortic arch, dextroaortia, corresponds to the persistence of aortic arches intended to disappear, and could be considered as a haemodynamic response to the early and untimely regression of another arch.