The Basic Theory of Acupuncture and Moxibustion

1. Meridian and Collateral Theory

What are meridians? Through long-term medical practice in the struggle against disease, the working people of ancient China gradually recognized that the human body contains channels through which “qi and blood” circulate. These channels are called meridians in Chinese medicine. They connect internally to the zang-fu organs and externally to the limbs and joints, crisscrossing and distributing throughout the entire body, performing the vital function of transporting qi and blood — analogous to the cardiovascular and lymphatic systems in the human body. At the same time, through the complex interconnections of the meridian system, the interior and exterior, the upper and lower, the front and back, the five zang and six fu organs, the four limbs and the skeleton, the five sense organs and nine orifices, and the sinews, vessels, skin, and flesh are all unified into a single organic whole, and adapted to the external environment — analogous to the nervous and endocrine systems.

Since the meridians play such an important role, they naturally form a profoundly intricate and complex system. This meridian system consists of two major parts: the jing mai (channels) and the luo mai (collaterals). The jing mai constitute the main body of the meridian system — they are large, run vertically and directly, and are located deep within the body. They can be further divided into the twelve regular meridians and the eight extraordinary meridians, along with the twelve divergent meridians, twelve meridian sinews, and twelve cutaneous regions that belong to the twelve regular meridians. The luo mai are branches of the jing mai — they are small, run horizontally or obliquely, and are located superficially. They can be further divided into the larger fifteen collaterals, as well as the minute collaterals (sun luo) and superficial collaterals (fu luo) that are distributed throughout the entire body.

When the body becomes diseased, yin-yang imbalance, disharmony of the zang-fu organs, and relative excess or deficiency of qi and blood are all closely related to the meridians and acupoints. Only by thoroughly understanding the circulatory distribution and physiological functions of the meridians can one employ meridian theory to explain pathological changes, guide pattern differentiation and meridian attribution, and carry out acupuncture and moxibustion treatment.

2. Zang-Fu Pattern Differentiation and Treatment

The zang-fu organs are the general term for the internal organs. The ancients referred to them as “visceral manifestation” (zang xiang). “Zang” refers to what is stored internally, i.e., the internal organs; “xiang” refers to signs or manifestations, meaning the external signs manifested by the physiology and pathology of the internal organs. In Chinese medicine, the heart, liver, spleen, lung, and kidney are designated as the five zang organs; the small intestine, gallbladder, stomach, large intestine, bladder, and sanjiao are designated as the six fu organs. The characteristic feature of zang-fu theory is its centering on the five zang organs, coordinating with the six fu organs, and linking with the five body constituents, five sense organs, nine orifices, and so forth, connecting them all into an integrated whole of the “five zang system.” Although the names of the zang-fu organs described are the same as those of organs in Western medicine, their physiological and pathological connotations differ greatly.

Zang-fu pattern differentiation and treatment is the foundation of all pattern differentiation and treatment in Chinese medicine. It is based on the physiological functions and pathological manifestations of the zang-fu organs, integrating theories such as the eight principles, disease causes, and meridians. Through comprehensive analysis of the four examinations, it analyzes and summarizes disease manifestations, thereby inferring the etiology, pathogenesis, location and nature of the disease, and the waxing and waning of zheng (righteous) and xie (pathogenic) qi, in order to determine the exact syndrome presented. Treatment principles and prescriptions are then decided based on the syndrome.

Acupuncture applies extensively in zang-fu pattern differentiation and treatment. For instance, the points where the qi of the zang-fu organs and meridians infuses into the body surface are called acupoints, which are the sites where acupuncture is applied. Acupoints are closely related to the zang-fu organs. In disease states, acupoints can reflect pathological conditions. The general pathway is: pathogenic qi → meridian system → dysfunction of zang-fu organs → symptoms often manifest at acupoint locations. During treatment, the meridian system is regulated to expel pathogenic qi and secure the zang-fu organs.

3. Yin-Yang and the Five Elements

Yin-yang and the Five Elements constitute a fundamental philosophical theory from ancient China, a summary of the ancients' observations and understanding of the natural world accumulated through long-term life and production practice. It served as a methodology for the ancients to recognize and interpret the natural world. The ancients used the Five Elements theory primarily to expound on “engendering and transformation” (sheng hua, i.e., regular generation and change), and the yin-yang theory primarily to expound on “extreme change” (ji bian, i.e., fundamental qualitative transformation) — roughly analogous to the modern concepts of “quantitative change” and “qualitative change.” Once applied to the field of Chinese medicine, it became the theoretical foundation of the zang-fu and meridian theories, and served as a methodology for understanding the entire life process and disease process — that is, the whole course of birth, aging, illness, and death — elucidating the physiological phenomena and pathological changes of the human body, and guiding the pattern differentiation and treatment of disease.

The yin-yang theory holds that the natural world is material, and that it arises, develops, and transforms through the interaction of yin qi and yang qi. As a natural science, Chinese medicine naturally absorbed this simple yet advanced philosophical theory. The human body is a unified whole. Whether the exertion of physiological functions or the evolution of pathological processes, everything resides within the process of yin-yang transformation. Thus, Chinese medicine considers that the occurrence of all diseases is the result of yin-yang disharmony. The application of acupuncture to treat disease is always aimed at restoring the yin-yang balance of the organism. In acupuncture clinical practice, methods such as contralateral needling and anterior-posterior or upper-lower corresponding point selection are commonly employed. These represent the acupuncture principle of the mutual induction of yin and yang, fully embodying the core idea in acupuncture therapy of emphasizing the balancing of yin and yang.

The fundamental significance of the Five Elements theory lies in using the five basic substances of the natural world to represent five abstract functional attributes, in order to reflect the phenomena of mutual generation and mutual restraint (xiang sheng xiang ke) between things and their regular patterns. The Five Elements theory plays an extensive guiding and important role in acupuncture clinical practice.