What happens to the diaphragm during inhalation?

During inhalation, the diaphragm contracts and moves downwards. This contraction of the diaphragm increases the volume of the thoracic cavity. As the diaphragm flattens and descends, it creates a negative pressure within the pleural cavity relative to the atmospheric pressure outside the body. This change in pressure enables air to flow into the lungs.

The downward movement of the diaphragm is crucial for effective breathing, as it allows the lungs to expand fully. Along with the external intercostal muscles, which elevate the ribs, the downward movement of the diaphragm helps facilitate air entry into the respiratory system. Understanding this mechanism is fundamental for grasping how respiratory dynamics work, and it underpins many clinical assessments and interventions related to breathing physiology.