Fig. 1

a–h Trans-abdominal color Doppler and gray scale images showing a external iliac vein (eiv.) (coded in blue) just dorsal to the external iliac artery (eia) (coded in red) and the internal iliac vein (iiv) (coded in red) and the common iliac vein (civ) formed by the union of the two veins. b Left renal vein (between red lines) as it passed anterior to the aorta (ao) to join the IVC (ivc). c Retro-aortic left renal vein (open white arrow) (RALRV) passing posterior to the aorta (ao) anterior to the spine to join the IVC (ivc). d Measurement of the aorto-mesenteric angle (red lines) between aorta (ao) and superior mesenteric artery (sma). e Measurement of the aorto-mesenteric window (black lines) between aorta (ao) and superior mesenteric artery (sma). f Showing the left gonadal vein (open black arrow) (lt gv) anterior to the left psoas muscle on the left side of the aorta. g Showing right gonadal vein (open black arrow) (rt gv) anterior to the right psoas muscle on the right side of the spine. h Showing duplicated left gonadal vein (lgv) (open green arrows) just to the left of the aorta (aort) (open green arrow)