The concepts of exterior and interior describe the depth of disease location and the severity of the condition.
Generally speaking, the skin, muscles, and superficial meridians belong to the exterior.
The organs, blood vessels, bone marrow, and internal meridians belong to the interior.
The exterior syndrome indicates that the disease is at the surface, with a shallow location and mild condition; the interior syndrome indicates that the disease is in the organs, with a deep location and severe condition.
Today we will learn about the knowledge points related to the Eight Principles of Diagnosis.
The Eight Principles of Diagnosis is a method of comprehensive analysis based on the materials obtained from the four examinations, aiming to explore the nature of the disease, the location of the pathological changes, the severity of the disease, the strength of the body’s response, and the comparison of the forces of righteousness and evil. It categorizes conditions into eight types: yin, yang, exterior, interior, cold, heat, deficiency, and excess. This is a fundamental method of diagnosis in TCM, encompassing various diagnostic methods and summarizing their commonalities, playing a role in simplifying complex conditions and highlighting key points during the diagnostic process.
The term syndrome (证, zhèng) refers to evidence or symptoms; it is not merely a symptom or subjective feeling, but a group of signs and symptoms. It is also TCM’s way of diagnosing diseases. A syndrome is a set of specific clinical manifestations (symptoms, signs, etc.) that includes aspects such as etiology, location of the disease, nature of the pathological changes, and the comparative strength of righteousness and evil. The concept of syndrome is derived from analyzing symptoms and signs, summarizing them into a concept that better explains the essence of the disease than the symptoms alone.
Although the manifestations of diseases are extremely complex, they can generally be categorized into the eight principles. The overall categories of diseases include yin syndrome and yang syndrome; the depth of the disease can be classified as exterior or interior; the bias of yin and yang, with yang excess or yin deficiency leading to heat syndrome, and yang deficiency or cold-heat imbalance leading to excess syndrome or deficiency syndrome.
Therefore, the Eight Principles of Diagnosis analyze the ever-changing diseases according to the simple dichotomies of exterior and interior, cold and heat, deficiency and excess, yin and yang, revealing the contradictions within the pathological changes, thus capturing the essence of whether the condition is exterior or interior, cold or heat, deficiency or excess, and whether it belongs to yin or yang. This is the fundamental spirit of the eight principles.
Exterior and Interior
The concepts of exterior and interior describe the depth of disease location and the severity of the condition.
Generally speaking, the skin, muscles, and superficial meridians belong to the exterior; the organs, blood vessels, bone marrow, and internal meridians belong to the interior. The exterior syndrome indicates that the disease is at the surface, with a shallow location and mild condition; the interior syndrome indicates that the disease is in the organs, with a deep location and severe condition.
Exterior Syndrome
The exterior syndrome is characterized by a shallow location of the disease in the skin. Generally, it occurs when external pathogens invade the body through the skin and nose, leaving the evil at the surface, resulting in a series of symptoms where the righteous qi (卫气, wèi qì) resists the evil, often seen in the initial stage of external diseases.
The exterior syndrome is characterized by a sudden onset, short duration, shallow location, and mild condition. It is commonly seen in the early stages of external heat diseases, such as upper respiratory infections, acute infectious diseases, and other initial stages of infectious diseases.
Main symptoms: fever and chills (or aversion to wind), headache, thin white tongue coating, and floating pulse are the basic symptoms, often accompanied by symptoms such as limb and joint pain, nasal congestion, and cough.
Due to the differentiation of external pathogens into cold and heat, and the varying strength of the body’s ability to resist these pathogens, the exterior syndrome can be further divided into exterior cold, exterior heat, exterior deficiency, and exterior excess syndromes.
Exterior Cold Syndrome
Main symptoms: severe aversion to cold, mild fever, significant pain in the head and body, no sweating, clear nasal discharge, and no thirst. The tongue is pale red, with a thin white and moist coating, and the pulse is floating and tight.
◆ Pathogenesis: Cold evil is constrained at the surface or in the knee, with righteousness and evil contending, hence the aversion to cold and fever. The evil qi invades the surface meridians, causing the circulation of the righteous qi and blood to be obstructed, leading to pain in the head, body, and limbs. The contention of righteousness and evil at the surface results in a floating pulse.
◆ Treatment principle: warm and release the exterior.
Exterior Heat Syndrome
◆ Main symptoms: significant fever, mild aversion to cold, headache, sore throat, sweating, thick nasal discharge, and thirst. The tongue is slightly red, with a thin white coating that is not moist, and the pulse is floating and rapid.
◆ Pathogenesis: Righteous and evil contend at the surface, hence the fever and aversion to cold. Heat evil invades the protective layer, causing sweating to escape. Heat injures fluids, leading to thirst. Heat evil at the surface results in a floating and rapid pulse.
◆ Treatment principle: cool and release the exterior.
Exterior Deficiency Syndrome
◆ Main symptoms: exterior syndrome with aversion to wind, aversion to cold, and sweating. The tongue is pale, with a thin white coating, and the pulse is floating and weak.
◆ Pathogenesis: The body is inherently weak, and the protective yang is not firm, hence the aversion to wind and sweating, with a floating and weak pulse.
◆ Treatment principle: harmonize the nutritive and protective qi, and release the muscle layer to expel the evil.
Exterior Excess Syndrome
◆ Main symptoms: fever, aversion to cold, body pain, and no sweating. The tongue is pale red, with a thin white coating, and the pulse is floating and strong.
◆ Pathogenesis: The evil is strong and the righteousness is not weakened; the evil constrains the muscle layer, with the righteous qi resisting the evil, and the sweat pores at the surface are tightly closed, hence the fever and aversion to cold without sweating, with a floating and strong pulse.
◆ Treatment principle: warm and release the exterior.
Distinguishing between exterior cold syndrome and exterior heat syndrome is based on the severity of aversion to cold and fever, as well as the tongue and pulse characteristics.
Exterior cold syndrome is characterized by severe aversion to cold and mild fever, while exterior heat syndrome is characterized by significant fever and mild aversion to cold. In exterior cold syndrome, the tongue coating is thin, white, and moist, and the pulse is floating and tight; in exterior heat syndrome, the tongue coating is thin, white, and not moist, and the pulse is floating and rapid. Additionally, the wind-cold evil can stagnate and transform into heat, leading to a transition from exterior cold syndrome to exterior heat syndrome when the external evil invades the muscle layer.
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