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: Anatomy
[{'content': 'In case of IVC obstruction, the collateral which opens up are all except - \nSelect and explain. \nA. Superior epigastric & inferior epigastric vein, B. Azygos & ascending lumbar vein, C. Superficial epigastric & ileolumbar vein, D. Lateral thoracic veins & prevertebral vein', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Whenever there is an obstruction in superior or inferior vena cava, collateral circulation opens up to connect inferior vena cava and superior vena cava. This helps in circulation being maintained by draining into the right atrium. The veins that can form collaterals include\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Superior epigastric\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Internal thoracic\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Lateral thoracic\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 thoracoepigastric\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Posterior intercostal\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Lumbovertebral\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Superficial epigastric\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Superficial circumflex iliac\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Deep circumflex iliac\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Inferior epigastric\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 External pudendal\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Azygous\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Hemizygous\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0 Ascending lumbar', 'role': 'assistant'}]