RESPIRATORY MUSCLES, CHEST WALL, DIAPHRAGM, AND OTHER

Abstract

Respiratory muscles are skeletal muscles whose function is to pump air in and out of the lungs. The chest wall muscles, diaphragm, and other muscles, including abdominal muscles, neck muscles, and upper limb muscles, may be broadly divided into inspiratory or expiratory muscles, according to whether their actions increase or decrease the capacity of the thoracic cage. The recruitment of individual muscles also depends on whether ventilatory requirements are high or low. Respiratory muscles share the common structural, physiological, and biochemical features of skeletal muscles, but are adapted to meet their unique task of being able to be active throughout life. These features determine their ability to generate contractile force, which is translated into inspiratory or expiratory pressure, and their resistance to fatigue. An imbalance between the load on the respiratory muscles and their capacity, resulting in breathlessness and ultimately respiratory failure, is a consequence of obstructive and restrictive respiratory disorders, and neuromuscular disease.