Sonograms of the fetus of coarctation of the aorta at the three-vessel trachea view. The large-sized pulmonary artery is visualized to connect with the descending aorta via the ductus. The aorta is on the right side of the pulmonary artery but is not visualized to drain into the ductus. AO: aorta; DAO: descending aorta; L: left; MPA: main pulmonary artery; R: right; SP: spine