The inferior extent of the pleura in the midclavicular line is at which rib?

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

Answer: (C)

The important idea is that the parietal pleura extends lower than the lung itself, forming the pleural recesses. In the front of the chest, along the midclavicular line, the pleura reaches down to about the eighth rib, whereas the lung ends around the sixth rib at that same line. So the pleural cavity sits two ribs lower than the lung border here. This is why the inferior extent of the pleura in the midclavicular line is at the eighth rib. Clinically, this difference helps define the costodiaphragmatic recess and guides procedures like thoracentesis, which avoid injuring the lung by staying within safe spaces above the lower borders.