Flow-Volume Loops in a Healthy Person (A), a Patient with Obstructive Lung Disease (B), a Patient with Restrictive Lung Disease (C), a Patient with a Fixed Obstruction (D), a Patient with a Variable Extrathoracic Obstruction (E), and a Patient with a Variable Intrathoracic Obstruction (F)

Flow-volume loops in a healthy person (A), a patient with obstructive lung disease (B), a patient with restrictive lung disease (C), a patient with a fixed obstruction (D), a patient with a variable extrathoracic obstruction (E), and a patient with a variable intrathoracic obstruction (F).FVC, forced vital capacity; MEF, maximal expiratory flow; MIF, maximal inspiratory flow; PEF, peak expiratory flow; RV, residual volume; TLC, total lung capacity.

(From the Merck Manual Professional Version [known as the Merck Manual in the United States and Canada and the MSD Manual in the rest of the world], edited by Robert Porter. Copyright 2019 by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co, Inc, Kenilworth, NJ. Available at http://www.msdmanuals.com/professional. Accessed November 11, 2014.)

section name header

Figure 1.2.