The diaphragm

The diaphragm is a dome-shaped muscle that separates the chest from the abdominal cavity and forms the main muscle of breathing. With each inhale it contracts and descends, with each exhale it relaxes and rises; this movement is the foundation of the breath. The diaphragm is also closely tied to emotional state; it tightens in tension and relaxes in calm. The free working of this muscle supports both the breath and a general relaxation. The diaphragm is the silent engine of the breath and of calm.