Seen in 2-3% of individuals (less common than circumaortic<unk><unk>  vein, seen in 5-7%)<unk>  derived from the<unk>  collar (circumaortic<unk>  venous ring) at an embryonic stage and completed by the regression and disappearance of the ventral (preaortic) limb and the persistence of the dorsal (postaortic) limb at a later stage
Drainage of lumbar veins may also be anomalous in these cases, although by variable anatomy
In some cases, the<unk>  exits the<unk>  hilum posterior to the<unk><unk>  artery (anomalous)
The<unk>  vein may receive flow from lumbar veins and may run caudad and enter the inferior vena cava in the lower lumbar region, or it may subdivide before entering the inferior vena cava.
Retroaortic left renal vein
Suprarenal veins
Internal iliac artery
Common iliac vein
Common iliac artery
Pelvic kidney
Pericardiacophrenic artery
Splenic artery