An unusual course of the right renal artery associated with an anomalous inferior vena cava.

In a 55-year-old male cadaver, the inferior vena cava bifurcated at a level midway between the hilus and inferior pole of the right kidney. The narrower branch, on the right side, drained the right renal and hepatic veins, ascended as the normal inferior vena cava, passed through the caval opening of the diaphragm and drained into the right atrium. The wider branch on the left side drained the left renal vein and penetrated the right crus of the diaphragm as the azygos vein. This vein ascended in the posterior mediastinum and drained into the superior vena cava. The hemiazygos and accessory hemiazygos veins were absent. In addition to these anomalies, the right renal artery entered the hilus after coursing through the above-mentioned two branches at the bifurcation. No congenital anomalies of the heart or abdominal viscera and main arteries were seen.