This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
[{'content': 'Left cardiac border bulge can be sen in all, except \nSelect and explain. \nA. Enlarged azygous vein, B. Left appendicular overgrowth, C. Coronary aery aneurysm, D. Pericardial defect', 'role': 'user'}, {'content': "Answer: A \nExplanation: A i.e. Enlarged Azygous Vein Azygous vein is a right sided structureQ and all others are left sided. Azygous vein lies in the angle between the right main bronchus & trachea and size is < 10mm diameter on erect X-ray. Its size decreases on valsalva, in spiration; and increases in supine position, pregnancy, poal hypeension, IVC & SVC obstruction, right hea failure, constrictive pericarditis and enlarged subcranial nodes. So Azygous vein can't give rise to left cardiac bulge.", 'role': 'assistant'}]