Which of the following is NOT involved in the process of lung inflation?

During the process of lung inflation, the diaphragm, external intercostal muscles, and thoracic wall all play crucial roles in creating the negative pressure necessary for air to flow into the lungs.

The diaphragm is a dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. When it contracts, it flattens and moves downward, increasing the volume of the thoracic cavity. This increase in volume leads to a decrease in pressure inside the thoracic cavity compared to the outside atmosphere, enabling air to rush into the lungs.

The external intercostal muscles are located between the ribs and help elevate the rib cage during inhalation. When these muscles contract, they also increase the volume of the thoracic cavity, contributing to lung inflation by lowering the pressure within it.

The thoracic wall provides structural support and facilitates the expansion of the thoracic cavity during breathing. It includes the ribs and the muscles associated with them, which are vital for proper lung function.

In contrast, while the abdominal muscles may play a role in forced expiration or increasing intra-abdominal pressure, they are not directly involved in the initial process of lung inflation. Their primary function in breathing is more evident during exhalation, particularly in situations that require active or forceful breathing