Although your bony ribcage serves you well as chest armor, taken alone this assembly of bones is unable to draw in or release a single breath. To turn this bone-vessel into a breathing-machine, Nature first lays down two layers of muscle (the intercostals) that crisscross each other between adjacent ribs. One layer helps with inhalation and the other with exhalation.
In addition to the intercostals between the ribs, the multiple-muscled diaphragm stretches like a complex, elastic floor across the bottom of the cage, and serves as the most powerful and important breathing tool you have. Now your bony cage, with its strategically placed muscles, has become a powerful pump, able to move air in and out of your body, on command.
The elusive muscle floor of the diaphragm attaches around the bottom rim of the ribcage, and to the waist-level lumbar spine at the rear. This big diaphragm serves simultaneously as the elastic floor of your ribcage, and the elastic ceiling of your abdominal cage.
The constant rising and flattening action of this powerful sheath as it pumps the air in and out, gently massages the heart and lungs as it rises, and in turn, the stomach, liver, spleen and intestines as it flattens down. Absolutely amazing! We won’t spend much time with anatomy but you will be well served to have some understanding and control of your main breathing muscles.
Be well. Breathe beautifully.
Sandwich Muscles I
Upside Down Breathing