<qa>  What is the K2-K3 line?The author considers as follows. K1 is the concentration point of nerves coming from the right colon, while K2 is the concentration point of nerves coming from the left colon, i.e. inferior mesenteric plexus. K3 corresponds to the superior mesenteric ganglion. The K1-K3 line corresponds to the root of mesentery. The K2-K3 line corresponds to the abdominal aortic plexus. The line originating from K2 and running parallel to the K1-K3 line is the line that transverses a number of nerves originating from jejunum or ileum, entering side by side into the root of mesentery and running to the superior mesenteric ganglion. 