Questions: Multiple Select Question Select all that apply Which of the following muscles are active during forced expiration? - External intercostals - Diaphragm - External oblique - Transversus abdominis

The muscles active during forced expiration are:

• External oblique
• Transversus abdominis

Explanation for each option:

• External intercostals: These muscles are primarily involved in inspiration, not expiration. They help elevate the ribs during inhalation, expanding the thoracic cavity. Therefore, they are not active during forced expiration.

• Diaphragm: The diaphragm is the primary muscle of inspiration. During expiration, especially forced expiration, the diaphragm relaxes rather than contracts. Thus, it is not active during forced expiration.

• External oblique: This muscle is part of the abdominal wall and plays a significant role in forced expiration. It helps compress the abdominal contents, pushing the diaphragm upward and aiding in expelling air from the lungs.

• Transversus abdominis: This is another muscle of the abdominal wall that is active during forced expiration. It helps compress the abdominal cavity, assisting in pushing the diaphragm upward and forcing air out of the lungs.

In summary, the muscles active during forced expiration are the external oblique and transversus abdominis.