English
When a TCM physician consults patients, the first step is to differentiate external contraction from endogenous diseases (illnesses originating from internal body); because they have different principles of diagnosis as well as the treatments.
Generally, conditions from external contraction were divided into two categories, cold damage and febrile disease . And there are two diagnostic methods for identifying the disharmonies of external contraction, the Differentiation According to Six Meridians and Differentiation According to Four Phases discussed in the next section. TCM physicians like to use the former method to diagnose the cold damages, while the later method to diagnose the febrile diseases.
Zhang Zhongjing (150~219AD)
The Six Meridians diagnostic method was created early in the Han Dynasty by Zhang Zhongjing. He wrote a book named Treatise on Cold-induced and Miscellaneous Diseases, in which specially discussed about different types of external contraction. This book became the foundation for diagnosing this kind of diseases in later time.
Under normal circumstance, the meridians are responsible for blood and qi distributions and for communications of the body. However, when diseases happen, then acupoints can be the entrances forexogenous evils, the meridians be the pathways for disease progression or reflections of disease changes. The evils spread through the distribution of yang meridians (Tai Yang, Yang Ming, Shao Yang) and yin meridians (Tai Yin, Shao Yin, Jue Yin), invading from exterior to interior body, from meridians to organs, and from yang meridians to yin meridians, which result in certain patterns of clinical development in external contractions. Based on the struggling between body’s resistance and pathogenic factors, diseased locations, and other clinical features, external contractions are classified into six stages of pathological changes that correspond to one of these particular meridians. TCM physicians aim to identify what stage of a disease a patient has by the signs and symptoms, and then decide the treatment accordingly.
For cold damages, the evils enter through the skin and muscular striae, they pass along the meridians and eventually attack the organs. There are particular pathways of transmission for the evils that affect the body, that usually pass from the exterior part of body to the interior and in this process gradually deplete the healthy energy of body. The more interior the disease has progressed, the more severe the illness and damage to the organs. The intensity of evils, body’s resistance, as well as the treatment are determinate factors of the progression of disease.
According to the Six Meridians diagnostic method, below are the usual disease progression of external contractions:
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- 1. Tai Yang Meridians
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- 2. Yang Ming Meridians
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- 3. Shao Yang Meridians
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- 4. Tai Yin Meridians
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- 5. Shao Yin Meridians
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- 6. Jun Yin Meridians
Tai yang (small intestine & bladder meridians)
Tai yang disease refers to conditions caused by exogenous evils invading the superficial portion of the body, which is also known as syndrome of exterior .
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Yang Ming (stomach & large intestine meridians)
Yang Ming disease refers to conditions where the invaded wind and cold evils have converted into heat evils or dryness evils, and they transmit directly into the internal organs, affecting the regions ruled by Yang Ming meridians. This may also be caused by improper treatment leading to body fluid consumption. The Yang Ming diseases exhibit a fierce fighting between pathogenic factors and the body’s defense, which indicates the yang qi is still sufficient.
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Shao Yang (gall bladder & triple burners meridians)
Shao Yang disease refers to conditions due to unrelieved exterior syndromes that have transmitted into the interior. The evils turn toward the interior but have not completely reached the interior, like in the Yang Ming diseases. The pathological changes are neither on the exterior nor in the interior but stay in between, regions like the gall bladder and triple burners are affected. They are known as syndromes of half exterior & half interior .
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Tai Yin (lung & spleen meridians)
Tai Yin disease refers to conditions involved the interior portion of the body, and present in cold, deficient (xu), or dampness disharmony. It is mostly due to cold evils attacking the middle burner in a constitutionally weak patient, or from delayed treatment of the three yang meridians diseases.
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Shao Yin (heart & kidney meridians)
Shao Yin disease refers to pathological changes in the heart and kidneys, which are extremely deficient conditions and characterized by systemic weakness.
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Jue Yin (liver & pericardium Meridians)
Jue Yin disease indicates the terminal stage of the six-meridian diseases, in which the body’s healthy energy is exhausted. There is a derangement in the yin yang balance. This condition is complex with syndromes of extreme heat or extreme cold, or syndromes of alternating cold and heat.
Below are the common disharmonies in the six meridian diseases:
| Diseased meridian | Presentations | |
| Tai Yang | Exogenous wind | Fever, aversion to wind, headache and spontaneous sweating. On examination, the pulse is floating and slow |
| Exterior coldness | Fever, aversion to cold, painful and stiff neck, body aching, unable to sweat and asthma. On examination, the pulse is floating and tense. | |
| Yang Ming | Interior heat and dryness | High fever, profuse sweating, extreme thirst, flushed face and chest fullness. On examination, a dry, yellow tongue coating and a floating and forceful pulse are present. |
| Excess heat in stomach and intestines | Feverishness of body, which is more pronounced in the afternoon, sweating, constipation, abdominal distention and pain that worsens when pressed, restlessness and delirium. On examination, a dry yellow tongue coating or yellow coating with thorns on the tongue and a deep and forceful pulse is present. | |
| Shao Yang / Half exterior & half interior | Bitter taste in mouth, dry throat, blurred version, alternating chills and fever, fullness in chest and under ribs, poor appetite, chest fullness and nausea. On examination, a white tongue coating and taut pulse is present. | |
| Tai Yin / Deficient cold in spleen and stomach | Abdominal distension with a preference for warmth and feels better when pressed, vomiting, anorexia and diarrhea. On examination, a pale tongue with a white coating and a slow and weak pulse is present. | |
| Shao Yin | Yang deficiency and interior coldness | Aversion to cold, spiritual fatigue, cold limbs, diarrhea, stool containing undigested food, nausea, thirst, preference for hot drinks and profuse and clear urine. On examination there is a pale tongue with a white coating and a deep and weak pulse. |
| yin deficiency with internal heat | Irritability, insomnia, dry mouth and throat and yellow and scanty urine. On examination there is a red tongue tip or a deep red tongue with little coating and a deep, thready and rapid pulse. | |
| Jue Yin | Extreme cold type | Cold limbs, low body temperature and aversion to cold. On examination, there is a pale tongue and an extremely thready, feeble pulse that can hardly be felt. |
| Extreme heat type | Cold limbs, irritability, feverish sensation, thirst and dark yellow urine. On examination, there is a yellowish tongue coating and rolling pulse. | |
According to the eight principles theory, diseases in the yang meridians belong to the exterior and are more often seen as heat and excess(shi) disharmonies. Diseases in the yin meridians belong to the interior and are more often seen cold and deficiency(xu) disharmonies. When there are changes in any of these six meridians, symptoms associated with the malfunctioning of the connected organs or other interrelated meridians will appear. The six meridian method is regarded as an incomplete method for identifying all organs or meridians diseases; because, this method mainly focuses on cold damages (shang han). Although the disharmonies of the six meridians differ, they are interrelated due to a constant changing process.
