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 coarctation of aoa which of the following is not involved in collateral formation? \nSelect and explain. \nA. Veebral aery, B. Posterior intercostal aery, C. Axillary aery, D. Subscapular aery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The coarctation may be:Preductal- where the narrowing is proximal to the ductus aeriosus or ligamentum aeriosum orPostductal- where the narrowing is distal to the ductus aeriosus or ligament= aeriosum.Collateral circulation connects the proximal and the distal aspects of the vessels over time. This collateral circulation will develop mainly from the', 'role': 'assistant'}]