The vertical vein is a vessel that functions in the embryonic period in the same way as the right superior vena cava. Normally, the vertical vein and the coronary sinus continue each other, but this vessel basically degenerates during the developmental process. In some cases it does not degenerate and still enters the coronary sinus, which is named the residual left superior vena cava when it is not combined with other malformations. If the vertical vein does not degenerate and does not continue with the coronary sinus, but continues with other vessels, most commonly the left pulmonary vein or pulmonary vein coaptation, it is still named the vertical vein. The vertical vein is both an embryonic vessel and a vessel that remains after birth, and sometimes the vertical vein can cause shunt abnormalities that can lead to cardiac symptoms.