The diaphragm is a key muscle and our principal breathing muscle. One feature of its anatomy, I have noticed from diagrams (see below), is that the tendons of the diaphragm, called the crura, wrap around the aorta as it descends through the body. Tighten this muscle and it looks like the aorta is put into a scissors grip by these tendons. I think this is one way we keep our blood vessels pressurized and our heads charged with energy. Free the diaphragm and we can take a lot of pressure off our blood vessels and our brains.
The crura are the strong tendons of the diaphragm muscle. See how they wrap around the aorta. Loosen and relax this muscle and we go a long way towards breathing easier and cooling our often over active and over heated brains.
Place the large roller against the lower rib cage in back and lean over to one side and allow the roller to press, roll and massage the lower ribs on that side and then the other. Feel for where there may be ache and stiffness in the ribcage and massage and roll for relief. The diaphragm attaches all around the inside of the lower ribs and then to the first 3 or 4 lumbar vertebrae via tendons (the crura). If it is chronically tense and short (as it is in many of us) it will eventually strain and distort the whole middle region of the back and trunk of the body. Press, roll, and massage those areas that feel stiff, achy, and tense in the ribs in back. Sense how the breathing eases and deepens as you relieve the stiffness and the ache.