Fig. 2

a The intraoperative view of the hilum structure shows there are no abnormalities of the pulmonary vein, artery, or bronchus. b The intraoperative view after the dissection of the subcarinal lymph node (#7). The dotted line shows the extent of the #7 lymph node. c The right vagus nerve (white arrow) is detected above the azygos vein. d The intraoperative view after dissection of the lower paratracheal lymph node (#4). The right RLN (black arrow) is observed to branch up from the vagus nerve (white arrow) and hook around the right-sided aortic arch. The dotted line shows the extent of the #4 lymph node. AA, aortic arch; Asc, ascending; AV, azygos vein; DA, descending aortic; RUB, right upper lobe bronchus; RUL, right upper lobe; RSPV, right superior pulmonary vein; SVC, superior vena cava