The apex of the lung extends upwards for one to two inches above the anterior extremity of the first rib, and is indicated by a curved line drawn from the upper border of the sterno-clavicular articulation to the junction of the inner and middle thirds of the clavicle, the highest part of the curve being from 1/2 inch to 1 1/2 inches above the clavicle. The apex of the right lung is 1/2 inch higher than that of the left. The subclavian artery lies on the cervical pleura covering the apex of the lung.
The anterior border of the right lung is indicated by a line drawn from the upper border of the sterno-clavicular articulation to the centre of the manubrium, and thence vertically downwards, slightly to the left of the middle line, to the level of the sixth' or seventh costal cartilage.
The anterior border of the left lung is indicated by a similar line as far as the fourth costal cartilage; thence along the lower border of the cartilage to the parasternal line, then downwards, to the upper border of the sixth costal cartilage in the parasternal line.
The lower border of the lung is the same on both sides, and is indicated by a line drawn from the lowest point of the anterior border along the sixth costal cartilage to the mid-clavicular line, and then curving slightly downwards across the chest to the spine of the tenth dorsal vertebra; this line crosses the eighth rib at the side and the tenth rib at the back.
The pleura is a little larger than the lungs, especially