Where is the apex of the lung located?

• A. At the level of the second rib
• B. At the level of the fifth intercostal space
• C. Near the superior aspect of the thorax, above the clavicle, at the level of the first rib
• D. At the inferior border near the diaphragm

Answer: (C)

The highest part of the lung sits up in the root of the neck, extending above the clavicle. In a typical adult, the apex reaches about 2–3 cm above the medial end of the clavicle, roughly at the level of the first rib. This places the apex in the superior aspect of the thorax, near the thoracic inlet, with the surrounding pleura extending into that region as well.

So the apex isn’t at the level of the second rib or the fifth intercostal space, nor at the diaphragm’s border. Those areas correspond to lower portions of the lungs or other landmarks, while the apex is the most superior part near the first rib and clavicle.