4L - Left lower paratracheal nodes

Station 4L (Left Lower Paratracheal Lymph nodes) are nodes lateral to the left border of the trachea and medial to the ligamentum arteriosum.

Boundaries:

• The upper border of station 4L is the upper margin of the aortic arch.

• The lower border of station 4L is the upper rim of the left main pulmonary artery (Note: on CT, in daily practice, the lower border of station 4L may be considered as the left tracheobronchial angle).

• The left lateral wall of the trachea (not the midline) serves as the boundary between stations 4R and 4L.