[Continuation of the azygos vein with agenesis of the inferior vena cave].

The authors present a case of agenesis of the inferior vena cava, above the kidneys, with deviation of the venous blood into a very dilated azygos vein. This anomaly is shown on a P.A. chest film by an opacity in the right tracheobronchial angle corresponding to the azygos prominence. the existence of an anastomosis between the azygos vein and the right auricle by the supra hepatic veins is demonstrated. The authors review the normal radiology of the azygos vein and the radiological approach necessary for the diagnosis of this malformation. In this study the CT scanner is the investigation of first choice, before cavography which demonstrates the associated venous anomalies. This anomaly is latent and therapeutic intervention is not required, but it is important to recognise it on a chest radiograph.