<prompt> Most commonly, ductus aeriosus isJust proximal to the left common carotidJust distal to the left subclanJust distal to the left common carotidJust proximal to the left subclan  <response>: 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 