How is the story of Pangu 盤古 separating the yang from the yin to create heaven and earth important?
Humans, unlike most animals, are blessed with a vertically oriented spine, rooted in earth, but reaching up to heaven. In establishing order, knowing up from down assumes foremost importance. Yang is light, and ascends. Yin is dense, and descends. Yang is heaven above. Yin is earth below. But up/down is only one dimension of yang/yin. When Pangu laid down to rest, his left eye transformed into the sun, his right eye the moon. The left side of the body and the sun are yang. The right side of the body and the moon are yin. The left-yang, right-yin distinction is commonly used in acupuncture. When only one side needs to be needled, men are needled on the left, women on the right. It also explains the placement of liver diagnostic areas on the left side of the cheeks and abdomen, since the liver is a yang zang organ; and the placement of lung diagnostic areas on the right, since the lung is a yin zang organ.
The distinction between clear yang and turbid yin is very important in Chinese medicine. Turbid means thick, or dense. Turbid does not mean dirty or bad. The head is heaven: it is the highest part of the body. It is the most yang part of the body, hence, it should be filled with clear yang. If it is, the brain and senses will function well. The person will be able to perceive the world and communicate clearly, and respond appropriately. If it is not, then we think either a blockage prevented the clear yang from rising, or that the body is unable to descend the turbid yin. Either way, the head is now filled with turbid yin. The senses will be clouded, the head will feel heavy, the person will not be able to think or speak clearly.
Phlegm is a excellent example of turbid yin. It can be in the familiar form that can be seen – thick and sticky or thin, clear or yellow, green, or brown, depended on whether it is associated with cold or heat. But there is also psychospiritual phlegm that has no physical form. Plum Pit Qi is a good example. It is the emotional or mental blocks that sticks to our sensory organs and confuse their functioning. Phlegm can generate and combine with wind or fire to create headache, dizziness, epilepsy, mania.
Spleen is the organ most responsible for raising the clear yang. A common scenario for the generation of phlegm is like this: Emotional frustration causes liver qi to stagnate, spleen functioning is blocked, spleen can not raise the clear yang and turbid yin can not descend. In time, turbid yin turns into phlegm.
The most important acupoint for getting rid of phlegm is Stomach 40, located at the middle and about an inch on the outside of the shin bone. The two main herbs for raising clear yang are Sheng Ma (Rhizoma Cimicifugae), and Chai Hu (Radix Bupleuri). They are often used together in combination with other herbs. Unlike western herbalism, very few Chinese herbs are ever used singly.