The rat liver has four lobes, including the median or cystic lobe, the left lateral lobe, the right lateral lobe and the caudate lobe. The left lateral lobe is the largest, and the caudate lobe is the smallest.
The left lateral lobe constitutes 30 percent of the entire weight of the liver. The median lobe occupies 40 percent of the total liver weight and is divided into two sub lobes separated by a deep fissure. The right lobe has two parts, the right superior lobe sharing 13 percent of total liver weight and the right inferior lobe sharing 6 percent of total liver weight. The caudate lobe is also called the Spiegel's lobe, which is located below the left lateral lobe. It occupies 7 percent of the total liver weight.