ANATOMY

Detailed explanation-1: -The rib cage muscles, including the intercostals, the parasternals, the scalene and the neck muscles, mostly act on the upper part of the rib cage (pulmonary rib cage) and are both inspiratory and expiratory. The abdominal muscles act on the abdomen and the abdominal rib cage and are expiratory.

Detailed explanation-2: -The major muscle group for exhalation is made up of the internal intercostals. These muscles pull down on the rib cage and thereby push air out of the lungs.

Detailed explanation-3: -The external intercostal muscles have an inspiratory action on the rib cage, whereas the internal intercostal muscles are expiratory.

Detailed explanation-4: -Internal intercostal muscles are the accessory respiratory muscles. Together with innermost intercostals, they enable forced expiration by depressing the ribs, thus shrinking the diameter of the thoracic cavity and pushing the air out of the lungs.

Detailed explanation-5: -The muscles of respiration are the muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity. The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during quiet breathing.