Which statement about lung lobes is correct?

• A. The left lung has a middle lobe.
• B. The right lung has a middle lobe.
• C. The left lung has three lobes.
• D. Both lungs have five lobes.

Answer: (B)

Lung lobes are separated by fissures, and the right side has an extra lobe. The right lung has three lobes—the upper, middle, and lower—split by a horizontal fissure between the upper and middle lobes and an oblique fissure between the middle and lower lobes. The left lung has two lobes—the upper and lower—separated by a single oblique fissure and shaped in part by the cardiac notch, which reduces space on that side. Because of these patterns, a middle lobe is present only on the right. So the statement that the right lung has a middle lobe is correct. The left lung does not have a middle lobe, and neither lung has five lobes.