retroaortic node /ret′rō·ā·ôr″tik/ [L, retro, backward; Gk, aerein, to raise] , a node in one of three sets of lumbar lymph nodes that serve various structures in the abdomen and pelvis. They lie below the cisterna chyli on the bodies of the third and the fourth lumbar vertebrae and receive the lymphatic trunks from the lateral aortic nodes and preaortic nodes. The efferent vessels from the retroaortic nodes end in the cisterna chyli. Compare lateral aortic node, preaortic node.