The segmental division of liver into eight segments is based on

Right hepatic vein divides the right lobe into anterior (V VIII) and posterior segments ( VI-VII) Middle hepatic vein divides the liver into right and left lobes. This plane runs from the inferior vena cava to the gallbladder fossa. The Falciform ligament divides the left lobe into a medial- segment IV and a lateral pa - segment II and III. The poal vein divides the liver into upper and lower segments. The left and right poal veins branch superiorly and inferiorly to project into the center of each segment. ref - researchgate.net