The ethmoidal veins drain into the superior ophthalmic vein.

Some small veins known as smallest cardiac veins drain directly into any of the four chambers of the heart.

Systemic veins drain the tissues of the body and deliver deoxygenated blood to the heart.

The left and right external jugular veins drain into the subclavian veins.

The diploic veins are found in the skull, and drain the diploic space.

The diploic veins drain this area into the dural venous sinuses.

Instead, these veins drain directly into the anterior wall of the right atrium.

The veins of the deep structures of the brain normally drain through the Galenic system.

This is in contrast to the right side of the body, where these veins drain directly into the IVC.

The smallest cardiac veins drain directly into the heart chambers.