Median sacral vein (medial sacral vein)

The median sacral vein (medial sacral vein) is a single blood vessel that ascends along the midline of the pelvic surface of the sacrum. It is formed by the union of several smaller veins at the apex of the sacrum. This vein has no named tributaries, and it typically ends by draining into the left common iliac vein (Read more!) at the level of the fourth lumbar vertebra (L4). However, it may occasionally terminate by draining into the angle between the two common iliac veins.

On its way to the common iliac vein, the median sacral vein is accompanied by the median sacral artery. Together, they contribute to the venous and arterial supply of the sacrum and adjacent structures.