One of my interests as an engineer and as a yoga teacher is figuring out correspondences between meridians and chakras.
My thoughts where that when integrated, the two systems could provide a useful tool for diagnosing problems and also a useful tool for sequencing yoga poses in a way that was energetically meaningful.
In Daoist thinking the five elements can be thought of as phases or principles. They can also be metaphorical anchors for understanding. Each of these elements has a particular quality, and while they may overlap, it is these qualities that can be helpful in diagnosing problems and also useful in linking the meridian system to the chakra system meaningfully.
The five elements in creative cycle order are:
fire, earth, metal, water, wood.
In the creative cycle each element "nurtures" the element that follows it. Thus fire produces earth from which metal is born. Metal melts and turns to water, and water is subsummed into wood (particularly in the form of a tree.)
For more about the five elements and how you can apply a basic understanding of them to yoga poses you can read five element theory.
Another way of looking at the elements is that two of them have outward moving tendencies, fire and wood. Another two have inward moving tendencies, water and metal. (Think of a sword piercing the heart.)
Also two of the elements are more energetic in nature, fire and water, and two of them more solid, metal and wood.
Actually earth is solid as well but I've left it out because it has a more fundamental quality. Think of it as the reference or foundation.
Building a building or an asana (a yoga pose) it helps if we are on solid ground. And it also help it the bottom part of our body is stable.
Earth has the quality of stability and for that reason I associate the root chakra with earth.
In the meridian system two organs and their meridians are associated with earth, the stomach and the spleen. The stomach is what we use to begin the process of utilizing food. And though oxygen is important for us to continue living life, it is the stomach which provides the materials necessary to build our body so that we can use it to breathe in the first place.
As a basic need, food is one of the first things on the list. That and shelter.
And so the earth element ties together the stomach, spleen and the root chakra.
The stomach meridian runs down the front of the body. The spleen meridian runs up the front of the inner thigh and then up the front of the body to the outside of the stomach meridian.
We can look at metal next in relating meridians and chakras. Metal, like earth, is solid. But unlike earth it has a direction, an inward moving tendency.
With respect to the seasons, metal relates to winter, a time when trees let go of their leaves and pull inwards, withdrawing from the world.
Metal reflects and can be associated with introspection, looking back on lessons learned and looking forward to choose future experiences.
Because it is introspective, metal can be thought of as a knife that cuts apart experiences to understand them. But when it comes time to doing things again, metal is also important because it can be used, like a nut and bolt, to hold things together.
In terms of balance, if we think of earth and the root chakra as our foundation, then the metal element is what unites the parts of our body so that they share a common center. So that we are balanced in whatever we do, the idea is then to keep our center over our foundation. Metal relates to the solar plexus (manipura) chakra.
In the meridian system, metal relates to the large intestine and lungs and their related meridians. The lung meridian runs down the outside line of the front of the arm. The large intestine meridian runs up the outer line of the back of the arm and thence up the neck.
I relate metal to the solar plexus chakra because this chakra is the center of the five chakras that exist in our body. (Two more chakras are located at the head.)
Continuing the correspondance of merdians and chakras we look now at the wood element. Often when I hear wood, I think of trees, living growing things that provide perches for birds and their homes, process co2 and provide shade among other things. Each year a tree grows outwards in the spring, and then pulls inwards in the fall. And for each year a growth ring is produced.
Wood (and trees in general) can be thought of as cylic and expressive in nature. In life we do things, then stop doing them and then do something else.
On a day to day, month to month and year to year basis we cycle through different experiences. When earth provides a foundation, a home for us to return to, it is actually venturing out that allows us to return to the comfort of home. Wood is thus expression or experience. it is the upper part of our body in a yoga pose. It is the building that is built upon the foundation. And like any living thing, the expression of ourselves, of our pose, changes, just like a tree does as it sways in the wind.
Wood is related to the liver and the gall bladder (not gull bladder as I used to spell it.) And I also relate it to the throat chakra, the chakra with which we can express ourselves vocally.
The gall bladder meridian runs down the side of the body. The liver meridian runs up the center line of the inner thigh and up the sides of the body to the shoulder.
Water is perhaps one of my favorite elements simply because of its association with flow. Getting into the flow is another metaphor for being present. When we are present we see what is happening now. Change happens now and when tune in to present what we observe and what we can become a part of is the flow of change.
Change is energy and energy is infomration. When we tune into the present energy carries infomration into ourselves and out of ourselves.
In the meridian system water is related to the bladder and the kidneys. In the chakra system water is related to the sacral chakra, the sexual chakra. This is the second chakra, just above the 1st or root chakra.
The bladder meridians runs down the back of the neck, torso and legs. The kidney meridian runs up the back of the inner thighs.
Note that for water to flow, it needs a channel, a river bed to flow through.
A river is both the river bed and the water flowing within it.
The complement of water is fire. Passion.
Where water moves downwards and inwards, pulled by gravity, fire burns upwards.
Where water never tires, fire will eventually burn out unless constantly given fuel to burn.
Ideally tended, fire can burn usefully and be put to good use. It relates to the heart and small intestine and their associated meridians. And it relates to the heart chakra.
Continuing to develop meridian and chakra correspondences there are two normal meridians and two chakras left to associate.
Those two meridians are those that connect to the pericardium and triple heater. These are "imaginary" organs. But I've found it helpful to associate them with the sides of the brain.
I also associate them with the third eye chakra and the crown chakra.
Rather than differentiating, I usually meditate on the halves of the brain, the two upper chakras and the pericardium and triple heater meridians as one unit.
While we have run out of elements to run correpsondances between meridians and chakras, there are two other qualities that may well be suitable to mention here. Yin and Yang. These are comparative qualites or "points of view." If we think of them as representing to sides of the coin, the coin itself represents a third element. Actually this isn't an element so much as it is the whole which holds yin and yang together.