Question

After running a marathon, a runner starts panting and as a result, his chest moves forward and backward. What causes this chest movement?

• A. Intercostal muscles and Rib cage
• B. Rib cage and Diaphragm
• C. Diaphragm and Intercostal muscles
• D. Intercostal muscles, Rib cage and diaphragm

Answer 1

The correct option is C Diaphragm and Intercostal muscles

When a person breathes in, the atmospheric air enters the lungs resulting in expansion of the chest. To create enough space for the lungs to expand, the muscles in the thoracic cavity undergo some changes. The intercostal muscles, rib cage and diaphragm work together to increase the volume of thoracic cavity. During inhalation, the following processes occur to help lower the pressure inside - internal intercostal muscles relax and external intercostal muscles contract, the ribcage moves forward and outward and the diaphragm contracts.