ANATOMY

Detailed explanation-1: -The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges.

Detailed explanation-2: -The diaphragm should be viewed as two distinct muscles, crural and costal, which act in synchrony throughout respiration. However, the activities of these two muscular regions can diverge during certain events such as swallowing and emesis.

Detailed explanation-3: -From a functional point of view, there are three groups of respiratory muscles: the diaphragm, the rib cage muscles and the abdominal muscles. Each group acts on the chest wall and its compartments, i.e. the lung-apposed rib cage, the diaphragm-apposed rib cage and the abdomen.

Detailed explanation-4: -The thin muscle below the lungs and heart that separates the chest from the abdomen.