Back Tension and the Meridians
Bladder 1, the point right at the tear ducts in the eyes, does wonders for the erectors, as the path of that lateral meridian follows the same path as that part of the back. Bladder 2, which is in that dip on either side of the bridge of the nose near the peak of the eyebrows, helps to release the paraspinals which run more medially nearer to the spine itself.
The left and right nadis - the ida and pingala - feminine and masculine channels of prana in the body that yoga helps to open, can be effected by bladder 2. Meridians have a physical structure with actual biochemical substances within them, whereas the prana of the nadis is more etheric and may not be seen under a microscope or by using dye. Bladder 2 is also anatomically very near the ethmoid bone which connects the bones and membranes inside the skull that can help release tension around and along the dura and dural tube within the spinal column.
When you do core strengthening exercises, compressive exercises like jogging, lift heavy objects, or sleep on your back, these pathways can become restricted. Stress can do the same as the sympathetic chain of ganglia run along the thoracic spine. If you do compressive activities, just remember to decompress afterwards! : )