At the midclavicular line, the inferior extent of the pleura corresponds to which rib level?

• A. Sixth
• B. Seventh
• C. Eighth
• D. Ninth

Answer: (C)

The important point is how the pleura lines the chest wall and how far it descends near the diaphragm. Along the midclavicular line, the parietal pleura reaches the eighth rib. This reflects the diaphragmatic pleura rising with the diaphragm and the costal pleura closing over the abdominal dome, creating the costodiaphragmatic recess. Clinically, this means fluid in the pleural space tends to collect in that recess and helps explain lines used in percussion and needle placement.

So, the inferior border of the pleural cavity at the midclavicular line is at the eighth rib, making that option the best fit. The lung itself extends to about the sixth rib at this line, so the pleura sits a bit lower than the lung margin there. The other rib levels don’t match the typical pleural reflection at this anterior line.