Which of the following respiratory muscles is not involved in normal inhalation? A) Internal intercostals B) External intercostals C) Scalenes D) Sternocleidomastoid

Understand the Problem

The question is asking which respiratory muscle among the given options does not play a role in regular inhalation. To resolve this, we need to analyze the function of each muscle listed: internal intercostals, external intercostals, scalenes, and sternocleidomastoid, as some are involved in exhalation rather than inhalation.

More Information

During normal inhalation, the diaphragm and external intercostals primarily facilitate lung expansion. The internal intercostals are involved in active or forced expiration, not inspiration.

Tips

A common mistake is assuming all intercostal muscles assist in inhalation. The internal intercostals aid in expiration, not inhalation.

Sources

• Muscles of Respiration - Physiopedia - physio-pedia.com
• Anatomy of breathing: Process and muscles of respiration | Kenhub - kenhub.com