Lateral sacral veins
The lateral sacral veins are paired blood vessels that arise along the inferior aspect of the sacrum. These veins ascend on the pelvic surface of the sacrum, accompanying the lateral sacral arteries. They pass laterally to the median sacral vein and median sacral artery, and form anastomoses with the median sacral vein along their course. They typically drain into the internal iliac vein (Read more!), although in some cases, they may drain into the superior gluteal veins instead.