Figure 9 Spirometrie tracing of lung volumes and capacities. The subject breathes with normal

Figure 9 Spirometrie tracing of lung volumes and capacities. The subject breathes with normal tidal volumes (TV). End-tidal volume is FRC. Adding the amount of air inspired from FRC until the lung is full (inspiratory capacity, IC) yields TLC, and subtracting the amount of air expired from FRC until the lung is empty (expiratory reserve volume, ERV) yields RV. The total amount of air able to be inspired and expired is the difference between TLC and RV, or the vital capacity (VC).