One of the fundamental TCM theories used to determine the pattern of disharmony is the theory of "Yin and Yang". Yin and Yang are terms used to describe two polar opposites. Each body part, each organ, and even each symptom in the body can be described in terms of Yin and Yang. Levels of Yin and Yang are constantly changing in the body and there are four possible states of imbalance:
Excess of Yin
Excess of Yang
Deficiency of Yin
Deficiency of Yang
It is rare for one of these states of imbalance to exist by itself. Excesses and deficiencies of Yin and Yang almost always appear in combination. For example, if a patient has loose stools associated with stomach flu this shows an excess of Yin. This excess Yin is a build- up of dampness which can be seen in the symptom of loose stools. If this patient also has a fever associated with the stomach flu, this shows an additional excess of Yang. The heat associated with this fever is an excess Yang symptom. In this example, a Yin excess and Yang excess are occurring simultaneously.Internal Organs
To look at the body as an integrated whole, one also looks at the theory of the Internal Organs. The TCM definition of an Internal Organ is very different from the Western concept. In Western medicine, an organ is a material-anatomical structure. In Chinese medicine each Internal Organ encompasses much more. There can be an anatomical structure, but there is also a corresponding emotion, tissue, sensory organ, color and element.
In addition, 12 of the Internal Organs correspond to the 12 main acupuncture meridians (or channels) that run through the body. There is qi (or energy) flowing through each meridian. If an Internal Organ is out of balance, the qi of that organ will be damaged.Therefore, the Chinese Lung (which is capitalized to distinguish it as the Chinese organ) shouldn't be equated with the Western Organ - although there are definite similarities.
Main article: Heart (Chinese medicine)
:: stores ( pinyin: cang) the shen ( Aggregate Soul, usually translated as mind)
:: governs (blood) and vessels/meridians
:: opens into the tongue
:: reflects in facial complexion
Main article: Pericardium (Chinese medicine)
Since there are only five zang organs but six yin channels, the remaining meridian is assigned to the Pericardium. Its concept is closely related to the Heart, and its stipulated main function is to protect the Heart from attacks by Exterior Pathogenic Factors. Like the Heart, the Pericardium governs blood and stores the mind. The Pericardium's corresponding yang channel is assigned to the Sanjiao (Triple Burner).
Main article: Spleen (Chinese medicine)
Governs transportation and absorption the extraction of jing wei ( lit. essence bits, usually translated with food essence, sometimes also called jing- and water - from food and drink, and the successive distribution of it to the other zang organs.
:: is the source of production and mutual transformation of and (blood)
:: contains the blood inside the vessels
:: opens into the lips (and mouth)
:: governs muscles and limbs
Main article: Liver (Chinese medicine)
:: Governs "unclogging and deflation" primarily of qi. The free flow of qi in turn will ensure the free flow of emotions, blood, and water.
:: stores blood
:: opens into the eyes
:: governs the tendons
:: reflects in the nails
Main article: Lung (Chinese medicine)
Metal. home of the Po ( Corporeal Soul), paired with the Large intestine
The function of the Lung is to descend and disperse qi throughout the body. It receives qi through the breath, and exhales the waste. The Lung governs the skin and hair and also governs the exterior (one part of immunity). A properly functioning Lung organ will ensure the skin and hair are of good quality and that the immune system is strong and able to fight disease. The normal direction of the Lung is downwards, when Lung qi "rebels" it goes upwards, causing coughing and wheezing. When the Lung is weak, there can be skin conditions such as eczema, thin or brittle hair, and a propensity to catching colds and flu. The Lung is weakened by dryness and the emotion of grief or sadness.
Main article: Kidney (Chinese medicine)
Water. Home of the Zhi ( Will), paired with the bladder
The Kidneys store Essence, govern birth, growth, reproduction and development. They also produce the Marrow which fills the brain and control the bones. The Kidneys are often referred to as the 'Root of Life' or the 'Root of the Pre-Heaven Qi'. Kidneys house the Will Power (Zhi).