Differentiation of Six-meridian Disharmony
When TCM physicians consult their patients, the first step is to differentiate whether their problems are originated from exogenous disease or internal injury (illnesses originating from internal body); because they have different principles of diagnosis as well as the treatments. Based on the manifestations of exogenous diseases, their pathological changes usually go from outer to inner body, and the course of development shows certain phases.
TCM further divides exogenous diseases into two types, cold damage (shang han) and febrile disease. There are two diagnostic methods for identifying the disharmonies of exogenous diseases, known as Differentiation of Six-meridian and Differentiation of Four-phase. Physicians like to apply the former method to diagnose the cold damages, while the later method to diagnose the febrile diseases.
The earliest record about the Six-meridian diagnostic method was in the Han Dynasty by Zhang Zhongjing (150~219 AD). He wrote a book named Treatise on Cold-induced and Miscellaneous Diseases, in which specially discussed about different types of exogenous diseases, which became the foundation for diagnosing this kind of diseases in later time.
Below summarized the six development stages in the exogenous diseases:
TCM further divides exogenous diseases into two types, cold damage (shang han) and febrile disease. There are two diagnostic methods for identifying the disharmonies of exogenous diseases, known as Differentiation of Six-meridian and Differentiation of Four-phase. Physicians like to apply the former method to diagnose the cold damages, while the later method to diagnose the febrile diseases.
The earliest record about the Six-meridian diagnostic method was in the Han Dynasty by Zhang Zhongjing (150~219 AD). He wrote a book named Treatise on Cold-induced and Miscellaneous Diseases, in which specially discussed about different types of exogenous diseases, which became the foundation for diagnosing this kind of diseases in later time.
Under normal circumstance, the meridian system is responsible for blood and qi distributions and for the communications of body. However, when diseases occur, the meridians and their acupoints become the entrances for exogenous evils attacking, the meridian pathways facilitate disease development and reflect disease changes. The evils spread through the distribution of 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 of the exogenous diseases. Based on the struggling between body’s resistance and pathogenic factors, diseased locations, and other clinical features, the exogenous diseases 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, wind and cold evils enter through the skin and striae, they travel along the meridians and eventually attack the organs. There are particular progression for the exogenous evils affecting the body, that usually spread 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.
The six-meridian diseases, including three yang meridians (tai yang, yang ming, shao yang) and three yin meridians (tai yin, shao yin, jue yin), summarize the general developmental stages of cold damages (shang han). Each of them repersents the confronting forces between the evils and body’s defense, involved regions, and disease progression inside the body.
Generally, disease in the three yang meridians often indicates a fierce condition and the body still remains in a strong fighting force; disease in three yin meridians often indicates a weakened condition and the body’s resistance is weak.
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1. 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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2. Shao Yang (gall bladder & triple burner meridians) Shao Yang disease refers to conditions due to unrelieved exterior syndromes that begin to turn towards the interior, but not yet completely reached the interior like in the Yang Ming disease. 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 syndrome of half exterior & half interior. |
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3. Yang Ming (stomach & large intestine meridians) Yang Ming disease refers to conditions where the invaded wind and cold evils have converted into fire evil or dryness evil, and they can spread to the internal organs directly, affecting the regions ruled by the Yang Ming meridians. This may also be caused by improper treatment leading to body fluid depletion. The Yang Ming diseases often exhibit a fierce fighting between pathogenic factors and the body’s defense, which indicates the yang qi is still sufficient. |
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4. 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 disharmonies. The conditions are often resulted from cold evils attacking the middle burner in a weakened patient, or from delayed treatment of the above three yang meridians diseases. |
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5. Shao Yin (heart & kidney meridians) Shao Yin disease refers to pathological changes usually involved 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, individuals usually show complex and mixed syndromes, such as extreme heat or extreme cold, or alternating cold and heat. |
Disharmonies of the six-meridian diseases
| Diseased meridian & Disharmonies | Presentations | |
| Tai Yang | Exogenous wind | Fever, aversion to wind, headache and sweating. On examination, the pulse is floating and slow. |
| Exterior coldness | Fever, chills, headache, neck stiffness, breathing difficulty, body aching, lumbar and joint pain. On examination, the tongue coating is thin and white, the pulse is floating and tense. | |
| Yang Ming | Interior heat and dryness | High fever, profuse sweating, extreme thirst, flush face and vexation. On examination, the tongue coating is yellow and dry, the pulse is surging and forceful. |
| Excess heat in stomach and intestines | A feverish body, hot flush in the afternoon, constipation, abdominal distention and pain that worsens when pressed, restlessness, even delirium or unconsciousness. On examination, the tongue coating is dry and yellow or yellow with thorns on it; the pulse is deep, excess and forceful. | |
| Shao Yang Half exterior & half interior |
Bitter taste in mouth, dry throat, blurred vision, alternating chills and fever, fullness in chest and under ribs, poor appetite, vexation and nausea. On examination, a white tongue coating and taut pulse is present. | |
| Tai Yin Deficient cold in spleen and stomach |
Abdominal distension with occasional pain and feels better when heating or pressing, vomiting, poor appetite and diarrhea. On examination, the tongue is pale and has a white coating, the pulse is slow and weak. | |
| Shao Yin | Yang deficiency and interior coldness | Aversion to cold, spiritual fatigue, cold limbs, diarrhea, stool containing undigested food, nausea, thirst that prefers hot drinks, profuse and clear urine. On examination, the tongue is pale and has a white coating, the pulse is deep and thready. |
| Yin deficiency with internal heat | Vexation, insomnia, dry mouth, sore throat, abdominal distension, constipation, yellow and scanty urine. On examination, there is a red tongue tip or a deep red tongue with little coating, the pulse is thready and rapid. | |
| 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, the tongue coating is yellow, and the pulse is rolling. | |
According to the eight diagnostic principles, diseases in the yang meridians (tai yang, yang ming, shao yang) often belong to patterns of exterior, heat and excess(shi), which are more often seen in disharmonies of the six fu organs. Diseases in the yin meridians (tai yin, shao yin, jue yin) often belong to the pattens of interior, cold and deficiency(xu), which are more often seen in disharmonies of the five zang organs. 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.
Differentiation of Six-meridian is regarded as an incomplete diagnostic method for identifying 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.
