Figure 31.

The AP window is bounded superiorly by the inferior margin of the aortic arch (dotted blue line) and inferiorly by the superior margin of the left pulmonary artery (dotted orange line); the ligamentum arteriosum is seen in an imaginary line between the arch of the aorta and the left pulmonary artery. In this case the ligamentum arteriosum is indicated by yellow arrows. The lymph node line medial to ligamentum arteriosum is labelled as station 4L and the lymph node lateral to the ligament is labelled as station 5