A. The systemic aorta. Owing to the body being inclined forwards, the root of the aorta appears to approach too near the lower boundary (N) of the thorax.
B. The left brachio-cephalic vein.
C. Left subclavian vein.
D. Right brachia-cephalic vein.
E. Left common carotid artery.
F. Brachio-cephalic artery.
G G*. The first pair of ribs.
H. Superior vena cava.
I. Left bronchus.
K K*. Fourth pair of ribs.