Draining of a retroaortic left renal vein via the 'subcentral veins' into the inferior vena cava

During an anatomical dissecting course for medical students, a retroaortic left renal vein (RALRV) draining via 2 channels into the inferior vena cava (IVC) was found in association with renal ectopy. The review of the embryology of the interrelation between the developing IVC and the ascending primitive kidney, with reference to the modi®- cation of the primitive renal veins, showed that the 2 branches of the left renal vein (LRV) could derive from the so-called `subcentral veins' (Williams et al. 1995). The subject was a 45-y-old white woman who had died from acute hepatic failure. The left kidney was located in the caudal part of the lumbar region. The abdominal viscera were removed en bloc, together with the diaphragm muscle and the retroperitoneal viscera and vessels. Before proceeding to the dissection of the viscera, the bloc was examined from the posterior aspect to demonstrate the aorta with its branches and the IVC with its tributaries (Fig. 1). The LRV (of 11 mm transverse diameter), after receiving the ovarian vein, passed behind the aorta and at this level divided into 2 vessels (both of 6 mm transverse diameter), which diverged at an acute angle and emptied independently in the IVC, 3±3 cm apart, forming a retroaortic juxtacaval venous ring. The rostral vessel was some 10 cm caudal with respect to the right renal vein, while the caudal one reached the IVC 4 cm rostral to its origin. No structures were found passing through the venous circle. The dissection of the IVC showed that the right inferior phrenic vein emptied into the ventral aspect of the IVC 5 mm below the diaphragm. The left inferior phrenic vein ended in the suprarenal vein, which reached the lateral aspect of the IVC some 8 mm caudal to the right one, showing an ascending course. The left adrenal gland was located 4 cm caudal to the contralateral gland. The outlets of 3 right and 2 left lumbar veins were recognisable in the posterior aspect of the IVC. The left ascending lumbar vein was poorly developed and showed no apparent connections with the renal vein. The right ovarian vein reached the ventral aspect of the IVC some 15 mm below the level of the right renal vein. The renal arteries showed a symmetric origin from the lateral surface of the aorta nearly 15 mm below the origin of the superior mesenteric artery. The right one passed behind the aorta and went to the renal hilum parallel to the posterior aspect of the right renal vein. The left renal artery was 10 cm long and showed a descending course towards the renal hilum. The ovarian arteries originated from the anterior aspect of the aorta 8 mm below the origin of the renal arteries. The right one passed in front of the IVC and went to the ovary medially to the ovarian vein. The left ovarian artery crossed the anterior aspect of the LRV medially to the ovarian vein and passed over the ventral surface of the ureter....