MedComic

Lung Volumes and Capacities

Jorge Muniz ·
Educational medical illustration of lung volumes and capacities showing tidal volume (TV), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), residual volume (RV), and the calculated capacities including inspiratory capacity (IC), functional residual capacity (FRC), vital capacity (VC), and total lung capacity (TLC) as measured by spirometry
Illustrated guide to lung volumes (TV, IRV, ERV, RV) and lung capacities (IC, FRC, VC, TLC) as measured by spirometry, showing the relationships between respiratory volumes during the breathing cycle. Proprietary medical illustration by Jorge Muniz, PA-C.

Lung volumes and capacities refer to the changes in lung volume during inspiration and expiration, and the absolute volume of air that the lungs hold during the respiratory cycle. These relationships are recorded using a device called a spirometer.

Lung Volumes

  • Tidal Volume (TV): The amount of air that moves in and out of the lungs during inspiration and expiration with quiet breathing
  • Inspiratory Reserve Volume (IRV): The air inspired with maximal inspiratory effort in excess of the tidal volume
  • Expiratory Reserve Volume (ERV): The additional air that can be forcibly exhaled after the expiration of a normal tidal volume
  • Residual Volume (RV): The volume of air remaining in the lungs after maximal exhalation

Lung Capacities

  • Inspiratory Capacity (IC): The amount of air that can be inspired from the end-expiratory level (IRV + TV)
  • Functional Residual Capacity (FRC): The volume of air remaining in the lungs after expiration of a normal breath (ERV + RV)
  • Vital Capacity (VC): The maximum volume exhaled after maximum inhalation (IRV + TV + ERV)
  • Total Lung Capacity (TLC): The maximum amount of air that can fill the lungs, approximately 6 liters (IRV + TV + ERV + RV)

Master ECG Interpretation with Sparkson

Get instant digital access to the complete Sparkson ECG guide, the full MedComic library, and educational games. One-time purchase.

Get Instant Access for $49