Double inferior vena cava is a congenital variation resulting from the persistence of the embryonic cardinal venous system. Duplication of the inferior vena cava is a rare occurrence where the left side cardinal venous system persisted as the left inferior vena cava.
Just above the union of the external and internal iliac veins on each side, the two symmetrical trunks were connected by a transverse trunk which is the embryological remnant of the inter posterior cardinal venous anastomoses and was situated dorsal to the common iliac arteries and ventral to the body of the fifth lumbar vertebra. These venous variations though generally silent may have significant clinical implications, especially during retroperitoneal surgery and in the treatment of thromboembolic diseases.
