Question
The image shows a congenital cardiac defect. Abnormal development of which branch of the aortic arch leads to this defect?
| A. | Right 4th aortic arch |
| B. | Left 6th aortic arch |
| C. |
Right 6th aortic arch |
| D. |
Left 4th aortic arch |
|
Correct Answer � B Explanation |
 |
The image depicts a Patent Ductus Arteriosus (PDA), a persistent fetal connection between the pulmonary artery and aorta
The ductus arteriosus arises embryologically from the left 6th aortic arch
Normally, it closes after birth due to increased oxygen tension and decreased prostaglandins
Failure to close leads to PDA, resulting in a left-to-right shunt, pulmonary overcirculation, and risk of heart failure
Incorrect Options:
– Option A → Right 4th aortic arch → right subclavian artery.
– Option C → Right 6th aortic arch regresses, not ductus arteriosus.
– Option D → Left 4th aortic arch forms aorta, not ductus arteriosus.