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
In case of coarctation of aoa which of the following is not involved in collateral formation? 
Select and explain. 
A. Veebral aery, B. Posterior intercostal aery, C. Axillary aery, D. Subscapular aery
A: Veebral aery
Answer: A: Veebral aery 
Explanation: 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