Mnemonic: 6 LITERs
Lung Capacity (TLC = 6L) = Inspiratory reserve volume (IRV = 3.3 L) + Tidal volume (TV = 0.5 L) + Expiratory reserve volume (ERV = 1 L) + Reserve volume (RV = 1.2 L)
Mnemonic: There are 4 lung volumes that do not overlap and 4 lung capacities that overlap.
Lung volumes
1. Tidal volume (TV): Air inhaled and exhaled during quiet breathing
2. Inspiratory reserve volume (IRV): Maximum volume of air that can be inspired in excess of normal inspiration
3. Expiratory reserve volume (ERV): Maximum volume of air that can be expired in excess of normal expiration
4. Residual volume (RV): Volume remaining after maximal expiration
Lung capacities
1. Inspiratory capacity (IC) = TV + IRV
2. Vital capacity (VC) = TV + IRV + ERV or IC + ERV
3. Functional Residual Capacity (FRC) = ERV + RV
4. Total lung capacity (TLC) = IRV + TV + ERV + RV or IC + FRC
