What is the role of external intercostal muscles during inhalation?

The role of external intercostal muscles during inhalation is to pull the ribs up and back. This action expands the thoracic cavity, allowing more space for the lungs to fill with air. When these muscles contract, they elevate the ribs, which increases the overall volume of the chest cavity and decreases the pressure inside the lungs relative to the outside atmosphere, facilitating the flow of air into the lungs. This process is essential for effective breathing and ensures that adequate oxygen is brought into the body.

Inhalation relies heavily on the coordinated effort of the external intercostal muscles and the diaphragm. While the diaphragm contracts and moves downward, the external intercostals assist by lifting the ribs, enhancing lung expansion. The correct answer reflects this critical function in the respiratory process.