Upper mediastinum above the aortic arch. The right subclavian artery has moved forward as it joined the left common carotid artery into the brachiocephalic trunk. Next, it will move toward the aortic arch, crossing the ventral side of the trachea in a frontal plane. Behind the right dissection plane lie the right vagus nerve and mediastinal pleura. AoA, aortic arch; BCV, brachiocephalic vein; BCT, brachiocephalic trunk; ln, lymph node; ln*, recurrent laryngeal nerve lymph node; RLN, recurrent laryngeal nerve; SA, subclavian artery; TD, thoracic duct; VN, vagus nerve; 2R, 2 L, right and left upper tracheal lymph nodes.