Introduction: The posterior thoracic wall, an area drained by the azygos venous system, is a common site for surgical intervention. Since the venous part of the cardiovascular system is subject to most common variation, abnormalities in the azygos venous system are often reported. Case presentation: During routine dissection classes for undergraduate medical students, we encountered a variation in the azygos venous system in a 65 years old south Indian male cadaver. We observed that there was no accessory azygos vein, and left 4 th, 5th, 6th and 7th posterior intercostal veins terminated directly into azygos vein. Conclusion: Identifying these types of variations is important during imaging this region and surgical operations of mediastinum.
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