<prompt> Structure that does not cross the midline isLeft gonadal veinLeft Renal veinLeft brachiocephalic veinHemiazygos vein  <response>: Left gonadal vein, left suprarenal vein right renal vein do not cross midline. Hemiazygos vein cross midline at The veebral level to join azygous vein. Left Renal vein is longer than right renal vein and cross midline anterior to aoa to drain into IVC. However, left gonadal suprarenal veins drain into left renal vein almost veically without crossing midline. Ref: Grays 39ep1026 