Azygos system of veins is the main source of venous drainage from the thoracic wall. Knowledge of azygos vein anomalies could be of importance to cardiothoracic surgeons and radiologists. We report a rare variation of azygos vein as seen in an adult male cadaver aged 65 years approximately. The azygos vein was formed by the union of left ascending lumbar and subcostal veins. It coursed upwards on the left side of descending thoracic aorta and crossed the left subclavian artery and the left vagus to terminate into the left brachiocephalic vein. It received left superior intercostal vein and left fifth to eleventh posterior intercostal veins. The hemiazygos and accessory hemiazygos veins were situated on the right side of the vertebral column. They received the right posterior intercostal veins and terminated into the azygos vein at the level of eighth thoracic vertebra.
The azygos system enlarges in cases of obstruction to the superior vena cava or inferior vena cava and result in increase blood flow through the system. Azygos continuation of the inferior vena cava is usually congenital and asymptomatic. The azygos vein is the sole drainage of the blood from the lower half of the body to the heart. It is crucial to identify the anomaly as it might involve in the surgical planning of tumours in the thorax or abdomen. Computed Tomography is a non-invasive technique and provide important information about the tumour and the vascular anomaly.