Muscles Used for Breathing
The main muscle of respiration is the diaphragm. Other muscles that aid in respiration include the external intercostals, scalenes, sternomastoids, abdominal muscles and internal intercostals.
Diaphragm
In quiet, gentle inhalation, the diaphragm contracts, lowering air pressure inside the lungs and drawing air in. When exhaling quietly, the diaphragm relaxes and the pressure reverses, expelling air.
External Intercostals
The external intercostals are between the ribs. During active inhalation, they expand the rib cage laterally, anteriorly and posteriorly.
Scalenes/Sternomastoids
These are the shrugging muscles. They serve to lift the sternum and the upper ribs during active inhalation.
Abdominal Wall
In active exhalation, the muscles of the abdominal wall--rectus abdominis, internal and external obliques and transverse abdominis--contract, raising abdominal pressure. This, in turn, raises the diaphragm, raising pressure in the lungs and expelling air.
Internal Intercostals
The internal intercostals are deep to the external intercostals. Like their counterparts, they draw the ribs in, expelling air during active exhalation.
Fun Fact
Hiccups are caused by an irritated diaphragm.
Tags: external intercostals, active exhalation, active inhalation, internal intercostals, Muscles Used, Muscles Used Breathing, Used Breathing