This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Radiology
Left cardiac border bulge can be seen in all, except - 
Select and explain. 
A. Enlarged azygous vein, B. Left appendicular overgrowth, C. Coronary aery aneurysm, D. Pericardial defect
A: Enlarged azygous vein
Answer: A: Enlarged azygous vein 
Explanation: Azygous vein is a Right sided structureand all others are left sided.It lies in thr angle between the right main bronchus and trachea and size is<10mm diameter on erect X-ray.