With deep inspiration, the posterior base of the lung drops to which vertebral level?

With deep inspiration, the posterior base of the lung drops to which vertebral level?

• A. T10
• B. T11
• C. T12
• D. L1

Answer: (C)

When you take a deep breath, the diaphragm contracts and moves downward, pulling the bases of the lungs with it. The diaphragmatic (lower) part of the lungs sits on the diaphragm, and behind the chest the lung base tracks down along the spine. With full inspiration the posterior base of the lung reaches the twelfth thoracic vertebra (T12). This downward shift reflects how much the diaphragm descends and how the lungs expand. Levels higher than that (T10 or T11) occur with less deep breathing, while L1 is well below the thoracic cavity and not reached by the lung base.

When you take a deep breath, the diaphragm contracts and moves downward, pulling the bases of the lungs with it. The diaphragmatic (lower) part of the lungs sits on the diaphragm, and behind the chest the lung base tracks down along the spine. With full inspiration the posterior base of the lung reaches the twelfth thoracic vertebra (T12). This downward shift reflects how much the diaphragm descends and how the lungs expand. Levels higher than that (T10 or T11) occur with less deep breathing, while L1 is well below the thoracic cavity and not reached by the lung base.