Lobes of the right and left lungs consist of...

• A. Right lobe: upper, middle, and lower; Left lung: upper and lower
• B. Right lobe: upper and lower; Left lung: upper and lower
• C. Right lobe: upper, middle; Left: upper and middle
• D. Right lobe: lower; Left: upper and lower

Answer: (A)

Lobes are defined by fissures that divide the lungs. The right lung has three lobes—upper, middle, and lower—separated by a horizontal fissure (between upper and middle) and an oblique fissure (between middle and lower). The left lung has two lobes—upper and lower—separated by an oblique fissure; it lacks a horizontal fissure. The left lung is slightly smaller because of the heart’s position, reinforcing why it has two lobes. So the standard arrangement is right with upper, middle, and lower; left with upper and lower.