This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Structure that does not cross the midline is: 
Select and explain. 
A. Left gonadal vein, B. Left renal vein, C. Left branchiocephalic vein, D. Hemiazygos vein
A: Left gonadal vein
Answer: A: Left gonadal vein 
Explanation: A i.e. Left gonadal vein- Left gonadal vein, left suprarenal vein & right renal vein do not cross mid line.Hemiazygous vein cross midline at T8 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 & supra renal veins drain into left renal vein (almost veically) without crossing midline