branches of the inferior mesenteric a anastomose in the marginal artery. mesenteric, superior. abdominal aorta at the level of the lower 1/3 of the L1 vertebral body. inferior pancreaticoduodenal a., middle colic a., jejunal a., ileal a., right colic a., ileocolic a. inferior part of the head of the pancreas, distal duodenum, jejunum, ileum, cecum, appendix, ascending colon, transverse colon