The sum of Vital Capacity (VC) and Residual Volume (RV) equals what?

The sum of Vital Capacity (VC) and Residual Volume (RV) equals Total Lung Capacity (TLC).

Vital Capacity represents the maximum amount of air that can be exhaled after a maximum inhalation and includes the Tidal Volume, Inspiratory Reserve Volume, and Expiratory Reserve Volume. Residual Volume is the volume of air remaining in the lungs after a maximal exhalation. When you combine these two measurements, you account for both the air that can be actively used during breathing (vital capacity) and the air that always remains in the lungs to prevent collapse (residual volume), thus giving you the Total Lung Capacity.

This concept is fundamental in understanding lung mechanics and is important in clinical assessments of respiratory function. It helps to provide insights into an individual’s pulmonary health and the full capacity of the lungs to hold air.