The right testicular vein, also known as the spermatic vein or the male gonadal vein, is responsible for carrying oxygen-depleted blood from the testicles to the inferior vena cava. The spermatic vein also carries deoxygenated blood to its various tributaries.

The vein begins in the back of the testes and then accepts tributaries from the epididymis. After joining the tributaries, the vein forms into a complex network of veins, called the pampiniform plexus. The pampiniform plexus is the largest mass forming the spermatic cord.

The testicular veins are paired veins, meaning each one supplies one of the testes.

A varicocele is a medical condition that the male can develop if the venous valves are not working properly and the blood starts to backflow or if the vein is compressed and the veins begin to swell. The symptoms of a varicocele include pain and swelling in the testicles, along with a heavy feeling. Over 90 percent of documented cases are within the left testicular vein.