In embryonic life developmental malformation of thoracic veins can lead to anomalies of the Superior vena cava and major thoracic veins like Azygos system. Double superior vena cava and double azygos vein are rare congenital anomaly with the incidence of 0. 3%. https://www.bekindtopets.com/limited-stock-Original-U-S-Vietnam-War-Era-Operation-Igloo-White-Seismic-Sensor-Inert-Rocket-great-price/