What role do the external intercostals play during inspiration?

What role do the external intercostals play during inspiration?

• A. They constrict the airways
• B. They increase abdominal pressure
• C. They elevate the ribs
• D. They assist in exhalation

Answer: (C)

The external intercostals play a vital role during inspiration by elevating the ribs. When these muscles contract, they pull the ribs upward and outward, which increases the volume of the thoracic cavity. This expansion creates a negative pressure within the lungs, allowing air to flow in from the outside environment. The anatomical positioning of the external intercostals makes them particularly suited for this function, as they lie between the ribs and run in a direction that facilitates rib elevation.

In contrast, other options such as constricting the airways, increasing abdominal pressure, or assisting in exhalation do not accurately describe the primary function of the external intercostals during the breathing process. Understanding the mechanical actions of the external intercostals highlights their essential contribution to inhalation and overall respiratory function.