diaphragm
The diaphragm is the horizontal pattern. The base is the upper lumbar spine, the 12th rib, the lower part of the costal bone, the lower part of the sternum and the gingival projection, and the stop is the center of the tendon in the middle of the diaphragm. In other words, since muscle fibers run radially from the center of the tendon, when the muscles contract, the center of the tendon descends, and thus the entire diaphragm descends and the thoracic cavity widens. When the muscles relax, the center of the tendon rises and narrows the chest cavity. When the diaphragm is lowered and the thoracic cavity is widened, the abdominal cavity becomes narrower, and the anterior abdominal wall naturally swells forward. When the diaphragm rises, the abdominal wall is closed. Breathing with the diaphragm as the main subject is called double breathing as if it seems to breathe through the abdomen. Adult males are said to have more than 60% respiration in a stable state.