In patients with interrupted aortic arch, which structure allows Wood to flow into the descending...

In interrupted aortic arch, the normal continuity between the ascending and descending aorta is disrupted. The patent ductus arteriosus (PDA) provides a vital conduit for blood to flow from the pulmonary artery to the descending aorta, maintaining systemic circulation distal to the interruption.

Persistent left superior vena cava and left carotid artery do not provide this flow. The foramen ovale is an atrial-level shunt and does not compensate for interrupted aortic arch.

This clinical anatomy is described in the "Textbook of Clinical Echocardiography, 6e", Chapter on Congenital Aortic Arch Anomalies【20:135-140†Textbook of Clinical Echocardiography】.