Which of the following statements describes a normal adult lung?

a. The left lung is bisected by two fissures.
b. The left lung has an upper, a middle, and a lower lobe.
c. The right lung has only an upper and a lower lobe.
d. The right lung has three lobes and two fissures.

ANS: D
Each lung is divided into two or three lobes (Figure 9-28), which are separated by one or more fissures. The right lung has upper, middle, and lower lobes. The left lung has only an upper and a lower lobe. Both lungs have an oblique fissure that begins on the anterior chest at approximately the sixth rib at the midclavicular line. These fissures extend laterally and upward until they cross the fifth rib on the lateral chest in the midaxillary line. The fissures continue on the posterior chest to approximately the third thoracic vertebra. The right lung also has a horizontal or "minor" fissure that separates the upper and middle lobes.