This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pediatrics
Most commonly, ductus aeriosus is 
Select and explain. 
A. Just proximal to the left common carotid, B. Just distal to the left subclan, C. Just distal to the left common carotid, D. Just proximal to the left subclan
B: Just distal to the left subclan
Answer: B: Just distal to the left subclan 
Explanation: Most commonly, the ductus aeriosus is just distal to the subclan, and the ductus enters the pulmonary aery at its bifurcation. Ref: Nelson textbook of pediatrics 21st edition Pgno: 2344