Functions and Clinical Applications of Channels and Collaterals

Table of contents
  1. Functions of Channels and Collaterals
  2. Clinical Application of Channels and Collaterals

The Spiritual Pivot-Channel Divergences (Líng Shū-Jīng Bié, 灵枢·经别) states, ‘It is by virtue of the twelve channels that human life exists, that disease arises, that human beings can be treated and illness cured.’ This statement demonstrates that channel and collateral theory comprises theoretical and practical aspects that validate each other and may be drawn upon for clinical purposes.

Functions of Channels and Collaterals

1. Linking the Interior with the Exterior throughout the Body

The tissues and organs in the human body, including the zang-fu and extraordinary fu organs, five sensory organs, nine orifices, skin, muscles, sinews and bones, have individual physiological functions, Nevertheless, they are interconnected and coordinated via the channel system. The twelve channels form the main body; the twelve channel divergences and the fifteen collaterals are the large branches; the twelve cutaneous regions and twelve channel sinews are the areas that correspond to each of the twelve channels on the skin, muscles, and tendons. The eight extraordinary vessels traverse, intersect, and connect the twelve channels. The channels and collaterals are independent of each other, but they interconnect and converge to form a network that integrates and links the whole body into a single organism.

The twelve channels connect the body surface to the internal organs and reinforce relationships among the zang-fu organs. The twelve channel divergences strengthen the relationship between the yin and yang channels and the connection among channels, zang-fu organs, and the head and facial region. The fifteen collaterals strengthen the relationship between the surface and the channels. The eight extraordinary vessels strengthen the relationships among the twelve channels.

2. Circulating Qi and Blood, Coordinating Yin and Yang

The Spiritual Pivot-The Various Conditions of Zang-Organs (Líng Shū-Běn Zàng, 灵枢·本脏) says, ‘The channels move qi and blood, nourish yin and yang, and lubricate the joints and tendons.’Qi and blood are the material foundation of all activities in the human body. The zang-fu organs and tissues conduct their normal physiological functions by relying on the nourishment provided by qi and blood, which are transported by the channels and collaterals throughout the body. Yin and yang differ throughout the human body. Channels and collaterals connect the whole body to facilitate yinyang balance, harmony, and normal physiological functions.

3. Resisting Pathogenic Qi, Reflecting Signs and Symptoms of Disorder

External pathogens usually attack the body through the channels and collaterals, penetrating from the exterior to the interior via the minute collaterals, collateral vessels, channels, and zang-fu organs. If channel qi is robust, it can defend the body and prevent pathogenic qi from penetrating deeply into the body; if it is weak, it cannot withstand the attack, and pathogenic qi remains, lingering at different levels in the channels and ultimately penetrating the zang-fu organs.

Because they communicate with the interior and exterior of the body, pathological changes within the zang-fu organs can be reflected on the body’s surface through the channels and collaterals. Internal disorders can manifest as tenderness, nodules, depressions, and saturated blood vessels on the body surface. Such signs and symptoms serve as important evidence for diagnosing internal disorders.

4. Transmitting Sensation, Regulating Deficiency and Excess

Channels and collaterals play an important role during treatment, as they react to acupuncture, moxibustion, and massage. The transmission of the needling sensation along the channels is shown in such phenomena as the arrival, movement, and spreading of qi to affected areas. Needling sensation is the key to therapeutic efficacy in acupuncture; it is conducted through the channels to diseased areas to regulate deficiencies and excesses. Notably, acupuncture’s regulating effects are optimizing: stimulating a point using the same method under different conditions can produce opposite therapeutic effects, but acupuncture always moves the body towards homeostasis and almost never has effects on healthy individuals. Hence needling PC 6 (nèi guān) increases the heart rate in bradycardia and reduces it in tachycardia, and needling ST 25 (tiān shū) can relieve constipation as well as arrest diarrhea.

Clinical Application of Channels and Collaterals

Channel theory applies to both diagnosis and treatment. TCM diagnosis includes channel and pattern differentiation; treatment includes point selection along channels and herbal selection based on channel tropism.

1. Channel and Collateral Diagnosis

The onset of disorders in zang-fu organs and their related tissues produces observable pathological changes along the course of the related channels including changes in color, bulging, depressions, papules, bleeding, saturation of blood vessels, and rough and peeling skin. The practitioner can examine the temperature and humidity of the skin with techniques such as fingernailpressing and the application of pressure in order to discover masses or tenderness beneath the skin that reveal diseased areas and their characteristics. Modern examination methods such as those that measure changes in electrical resistance and temperature may also be used. These expand traditional inspection methods and make the final diagnosis more objective.

2. Pattern Differentiation according to Channel

Channels and collaterals communicate with the interior and exterior, superior and inferior, anterior and posterior, and medial and lateral aspects of the body. Because every channel has its own distribution, zang-fu organ, and related tissues, disease symptoms can be differentiated, based on the running course and connections among the channels and collaterals, in order to determine to which channel or collateral they belong. This is known as pattern differentiation according to channel.

Disorders are reflected along the courses of the channels and in their corresponding zang-fu organs, collateral vessels, and channel sinews. The symptoms in cutaneous regions are in fact an overall reflection of channel and collateral disorders. The eight extraordinary vessels also intersect with the channels and are thus accountable for particular disorders. By differentiating the pattern according to channels, we can determine the region, characteristics, severity, development, and prognosis of a disease, all of which are important in diagnosis and treatment.

3. Selecting Points along a Channel

Points are selected on the basis of channel pattern differentiation; distal points are chosen from channels related to the disorder. Theoretically speaking, channel points have clinical actions on disorders that occur along the distribution regions of the channel; e.g., because the hand and foot shaoyang and hand taiyang channels enter the ear, many points on these channels have therapeutic effects on disorders of the ear such as deafiness, tinnitus, and otitis media. Selecting points along a channel is a basic point selection method in clinical practice.

4. Channel Tropism in Chinese Medicinals

Chinese medicinals have channel tropism, that is, a propensity to enter certain channels; thus channel and collateral theory may be used to explain, analyze, categorize, and summarize their properties and actions. Because disorders can be differentiated to the channels to which they belong, in theory Chinese medicinals that have clinical actions on particular disorders are assumed to enter the corresponding channels. This theory appeared during the Song Dynasty and was systematized in materia medica during the Jin and Yuan dynasties. Pouch of Pearls (Zhēn Zhū Náng, 珍珠囊), written by Zhang Jie-gu in 1168 CE, is recognized as the earliest book on the theory. It differentiates medicinals based on the properties of qi, flavor, yin and yang, thickness and fineness, ascending and descending, floating and sinking, supplementation and drainage, the six qi, and the twelve channels. It also explains how to use the medicinals according to these guidelines.

Li Dong-yuan (1180-1252 CE), who established the School of Nourishing Earth, wrote a book detailing the ascending/descending and floating/sinking properties of medicinals. He proposed that every channel has its envoy, its reporting and directing medicinal. Xu Ling-tai (1693-1771 CE), a physician in the Qing Dynasty (1644-1911 CE), used the theory of channel tropism to describe the six-channel pattern differentiation method for using medicinals in Treatise on Cold Damage (ShāngHán Lùn, 伤寒论), which was recorded in his book, Treatise on the Origin and Development ofMedicine (Yī Xué Yuán Liú Lùn, 医学源流论).

5. Qi Gong and Massage

‘Qi’ in the practice of qi gong refers to channel qi. After years of practice, a practitioner attains the ability to use the mind to direct channel qi and guide its flow within the body. At this level of expertise, the qi gong master can direct channel qi to diseased regions at will to prevent and treat disease, maintain health, and foster longevity.

Massaging along channels is another effective treatment method. Patients can perform selfmassage on the relevant channels and points under the direction of their doctors. This promotes the circulation of qi and blood, treats disease, and helps the individual stay healthy and fit.