Lung Diseases Affecting the Chest Wall

• Obesity hypoventilation syndrome
• Neuromuscular disorders

The respiratory pump, which is responsible for creating the bulk flow of gas from the atmosphere to the alveoli and back out, relies heavily on the chest wall. The operation of the pump is affected by diseases that alter the anatomy of the chest wall, which can lead to respiratory compromise or failure. Bony structures (ribs, spine), respiratory muscles, and nerves connecting the central nervous system to the respiratory muscles are all part of the chest wall. The various forces acting on the mechanical structure of the chest wall play a significant role in determining lung volume, and abnormalities in the chest wall can have a significant impact on lung function; in particular, chest wall pathology may be a significant contributor to restrictive respiratory physiology. These conditions can make it difficult to breathe without damaging the lungs. The limitation caused by a poorly distensible chest wall is the physiologic hallmark of these illnesses. Reduced chest wall compliance provides an elastic stress on the respiratory muscles, increasing the amount of labour required to breathe and predisposing these people to respiratory muscle fatigue. Intrinsic (muscular training) and/or extrinsic (increased central drive) mechanisms adjust the respiratory system to greater elastic stress.