Click image to view full screen

Retract the inferior vena cava and identify the paired lumbar veins which enter its posterior surface. There may be variation in this pattern. The first two or three lumbar veins may join the ascending lumbar veins which drain into the azygos vein on the right side, and the hemizygos vein on the left side of the vertebral column.

Links and References:
Grant's: 2.99
Netter (1ed.): 324,248,247 (2ed.): 320,248,247
Rohen/Yokochi: 311. 313