The perihilar region of the left kidney contacts the tail of the pancreas, a secondary retroperitoneal organ, without intervening peritoneum. This point of contact occurs posterior to the left extremity of the transverse mesocolon, a horizontally disposed derivative of the embryonic dorsal mesentery that suspends the transverse colon from the secondarily retroperitoneal viscera (i.e., duodenum and pancreas).

The inferolateral aspect of the left kidney contacts the descending colon, which is secondarily retroperitoneal, without intervening peritoneum. The inferomedial aspect of the left kidney contacts loops of jejunum through an intervening layer of inframesocolic peritoneum.