0 (of any structure in the body) existing as a single structure, not part of a pair:
If the obstruction is above the entry of the azygous vein, the syndrome is less pronounced.
This fetus had a right aortic arch and right duct, and interruption of the posterior caval vein with left azygous connection.
The great arteries were normally connected and there was hemi-azygous continuation of the inferior caval vein as well as bilateral superior caval veins present.
The single superior caval vein, which was left-sided and had an azygous vein draining into it, drained into the left-sided atrium.
