Figure 9. (a) Diagrammatic explanation of the embryological basis for aortic coarctation. Reproduced with permission, Moore KL. The developing human: clinically orientated embryology. WB Saunders Company, 1982. (b) Parasagittal cine MRI showing an aortic coarctation (arrow). (c) Detail of a chest radiograph showing left-sided inferior rib notching (arrows) due to collateral circulation in a patient with post-ductal aortic coarctation.