North Carolina EMT State Practice Exam

What is the primary muscle relied upon by children for breathing?

1. Intercostal muscles

2. Diaphragm

3. Abdominal muscles

4. Accessory muscles of respiration

The correct answer is: Diaphragm

The primary muscle relied upon by children for breathing is the diaphragm. This dome-shaped muscle sits beneath the lungs and plays a crucial role in the respiratory process. When the diaphragm contracts, it flattens and moves downward, increasing the thoracic cavity's volume and allowing air to flow into the lungs. Children are particularly dependent on the diaphragm for breathing because their rib cage and intercostal muscles are less developed compared to adults, making the diaphragm the most effective muscle for ventilation. Unlike adults, who often use both the diaphragm and intercostal muscles simultaneously, children primarily engage the diaphragm, which allows them to breathe efficiently despite their smaller lung capacity. In more complex or distressing breathing scenarios, other muscles, such as accessory muscles, may be recruited. However, in typical circumstances, especially at rest, the diaphragm is the primary muscle they depend on for normal respiratory function.