The outer surface of the lung covers the pleura, and is divided into lobules of unequal volume by the middle of the pleura. There are brachiocephalic veins, trachea, and esophagus on the inner surface of the right lung apex of the household ventilator, the left common carotid artery, left subscapular artery, trachea, and esophagus on the inner surface of the left lung apex, and the anterior inner surface of the lung apex has a subscapular groove.