second rib; intervertebral disc T 4/5; bifurcation of trachea; and azygos
vein joining superior vena cava. Since the tracheal lumen is air filled, it
appears black on CT images. The trachea is normally easy to follow inferi-
orly until it bifurcates into right and left main bronchi. This bifurcation
normally occurs at about the sternal angle, where the body of the sternum
meets the manubrium and where the second rib attaches, which is also the
approximate level of the intervertebral disc T 4/5. The other answers
(answers a, b, c, e)are notcorrect.
Thorax Answers 491