<prompt> The left testicular vein drains into which of the following veins?Left internal iliac veinLeft common iliac veinInferior vena cavaLeft renal vein  <response>: The left testicular vein drains into the left renal vein. The right testicular vein drains directly into the inferior vena cava. This difference in venous drainage is believed to explain the greater incidence of varicocele on the left side than on the right. The venous drainage from the penis is to the internal vein, which then drains into the internal iliac vein. 