Vasa vasorum of the artery wall (400X)

Vasa vasorum are small blood vessels that comprise a vascular network supplying the walls of large blood vessels, such as elastic arteries (e.g., the aorta) and large veins (e.g., the venae cavae).

The name derives from Latin 'the vessels of the vessels'. Occasionally two different singular forms are seen: vasa vasis (from Latin 'the vessels of a vessel') and vas vasis (from Latin 'a vessel of a vessel').

In elastic arteries such as the aorta, which have very regular elastic laminae between layers of smooth muscle cells in their tunica media, the internal elastic lamina is approximately the same thickness as the other elastic laminae that are normally present.