Which muscles are involved in forced exhalation?

During forced exhalation, the primary muscles involved are the abdominal muscles and the internal intercostal muscles. The transversus abdominis is one of the key abdominal muscles that play an important role in this process. When these muscles contract, they increase intra-abdominal pressure, pushing up against the diaphragm and facilitating the expulsion of air from the lungs.

The intercostal muscles, specifically the internal intercostals, assist by actively depressing the ribs and reducing the thoracic cavity's volume, which aids in expelling air. This is distinct from normal (passive) exhalation, where the diaphragm and external intercostals play a more significant role, allowing the lungs to deflate through elastic recoil without muscular effort.

Other options include muscles that do not play a direct role in forced exhalation. For example, the diaphragm and external intercostals are primarily involved in inhalation, while the gluteal muscles do not contribute to respiratory mechanics at all. The rectus abdominis, while an abdominal muscle involved in forced expiration, is not mentioned in the correct pairing with the intercostal muscles in this case. Therefore, the combination of the transversus abdominis and intercostals recognizes the active muscular