Which measurement indicates the maximum volume of air that can be inspired after a tidal expiration?

• A. Functional residual capacity
• B. Inspiratory capacity
• C. Residual volume
• D. Total lung capacity

Answer: (B)

The maximum volume of air that can be inspired after a tidal expiration is specifically referred to as inspiratory capacity. This measurement combines the volume of air remaining in the lungs after normal expiration, known as tidal volume, with the maximal volume of air that can be inhaled. Therefore, it provides a clear picture of how much additional air can be inhaled following a normal breath.

In contrast, functional residual capacity refers to the total volume of air remaining in the lungs after a normal tidal expiration, which includes both expiratory reserve volume and residual volume. Residual volume represents the air that remains in the lungs even after a maximum exhalation, and total lung capacity is the total volume of air the lungs can hold, which includes all lung volumes. These definitions clarify why inspiratory capacity is the most accurate measurement for the question posed, as it directly assesses the potential for additional inhalation beyond a typical breath.