both of them
an exhalation
The Phrenic Nerve-Diaphragm and the External Intercostal Nerve-External intercostal muscles
The diaphragm and external intercostal muscles are primarily involved in changing the thoracic volume during breathing. The diaphragm contracts during inhalation to increase thoracic volume, while the external intercostal muscles help lift and expand the rib cage.
External intercostal muscles are the ones between the ribs that help elevate them during inspiration.
There are 11 pairs of external intercostal muscles in humans. These muscles are located between the ribs and are involved in expanding the chest cavity during inhalation.
The internal intercostal muscles relax and the external intercostal muscles contract, pulling the ribcage upwards and outwards.
The diaphragm and the external intercostal muscles.
The diaphragm (a sheet of muscle underneath the ribcage) and intercostal muscles (located between your ribs).
Inhalation is caused by the contraction of the diaphragm and the external intercostal muscles. This causes the chest cavity to expand, creating a negative pressure that allows air to flow into the lungs.
The external intercostal muscles raise the ribs during inhalation, while the internal intercostal muscles lower the ribs during exhalation in a fetal pig.
Inspiration is due to the contraction of the diaphragm and external intercostal muscles.
Negative pressure produced by the contraction of certain muscles like the diaphragm muscle and the intercostal muscles.