Caudate lobe is segment I Quadrate lobe is segment IVa The caudate lobe (segment I) is the dorsal poion of the liver and embraces the IVC. It lies posterior to the left poal triad inferiorly and left and middle hepatic vein superiorly. Caudate lobe is unique in sense that it receives blood supply from both the right & left poal pedicles. bile ducts drain into both right & left hepatic ducts. its venous drainage is directly into the vena cava Ref : Schwaz 9/e p1095