What is the primary muscle involved in the process of inhalation?

The primary muscle involved in the process of inhalation is the diaphragm. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity. This expansion creates a negative pressure that allows air to be drawn into the lungs. As the diaphragm is the main muscle responsible for initiating inhalation, its action is crucial for proper respiratory function.

While other muscles, like the external intercostals, assist in the process by elevating the rib cage and further increasing lung volume, they do not play as fundamental a role as the diaphragm. The transversus abdominis and rectus abdominis primarily function in processes related to posture and core stabilization, rather than in active inhalation. Understanding the diaphragm's key role helps clarify how the respiratory system operates during breathing.