Here is a mnemonic for retroperitoneal structures "SAD PUCKER": Suprarenal glands (aka adrenal glands), Aorta and IVC, Duodenum, Pancreas, Ureters, Colon (descending, ascending), Kidneys, Esophagus, and Rectum. Not Shown in Diagram: Suprarenal glands aka adrenal gland, Urrters, Esophagus (lower 2/3), and Rectum (upper 2/3).