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How do the external intercostal muscles move the ribs during inhalation?
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Respiratory system
Different methods of respiration in animals.
During inhalation, the external intercostal muscles play a vital role in expanding the thoracic cavity. As these muscles contract, they cause the ribs to rotate upward and laterally. This movement increases the circumference of the chest, which helps lower the pressure within the lungs relative to the outside air, allowing air to flow into the respiratory system.12
While the diaphragm serves as the primary muscle of inspiration, the external intercostals act as essential assistants, augmenting the expansion of the rib cage to facilitate effective gas exchange.31