Fig. 9
From: Congenital systemic venous return anomalies to the right atrium review
a Interruption of the hepatic segment of the IVC/Azygos continuation of the IVC schematic. In this anomaly, the hepatic segment of the IVC is absent or hypoplastic, with the hepatic veins draining into the right atrium via the suprahepatic IVC and the renal portion of the IVC, receiving the blood return from the kidneys and lower extremities, by means of the azygos vein. b Interruption of the hepatic segment of the IVC/Azigos continuation of the IVC embryology schematic. The result from the failure to form of the right vitelline-subcardinal anastomosis, with consequential regression of the right subcardinal vein, causing the blood to directly shunt into the right supracardinal vein. c Interruption of the hepatic segment of the IVC/Azygos continuation of the IVC imaging. Contrast-enhanced CT scan denoting absence of the hepatic segment of the IVC (asterisk), drainage of the hepatic veins into the right atrium via the suprahepatic IVC [A, B] and continuation of the renal portion of the IVC, passing posterior to the diaphragmatic crura to enter the thorax as the azygos vein (triangle), which drains to the SVC as normal [C, D]