The Physiology of Meridians and Application of Meridian Theory
I. The Physiological Functions of Meridians and Collaterals The functional activities of the meridians is called "meridian-qi," which manifest in the linking up of the exterior with the interior and the upper with the lower meridians,and in connecting the viscera with organs, in transporting qi and blood, in nourishing the viscera and tissues, responding, conducting and regulating the functions of every part of the body and so on. 2. Circulating Qi and Blood,Nourishing the Viscera and Tissues All the tissues and organs need to be nourished in order to perform normal physiological activities. The qi and blood circulate within the whole body to nourish the viscera and tissues ,and defend against the exogenous-evil to protect the body. The body must rely on the transportation and transmission of qi and blood in the meridians and collaterals to remain healthy. Chapter 47 in Spirit Pivot states : "The meridians and collaterals transport blood and qi to adjust the yin and yang, nourish tendons and bones, and in prove joint functions. " 3. Response and Conducting Functions Response and conduction mean that the meridian system functions in response to and conduction of the needling sensation and other stimulations. The phenomena of"getting qi"and"activating qi" while needling is a reflection of the response and conducting functions of the meridians. 4. Regulating the Balance Meridians and collaterals circulate qi and blood and coordinate yin and yang to keep the relative balance of body activities. When a disease occurs in the body,the symptonms of disharmony of qi and blood ,and excess or deficiency of yin and yang emerge ,and car be treated by acupuncture and moxibustion therapy to stimulate the meridian regulative function. The principle is stated in Chapter 75 in Spirit Pivot "To reduce the excess and reinforce the deficiency makes yin and yang balance. "The experimental data proves that acupuncture can adjust the function of the zang-fu viscera by puncturing the relativt points on the meridians. That is through calming down the original excitation and exciting the original inhibitorystate. II. Application of Meridian Theory 1. Explaining the Pathological Changes In the normal conditions ,meridians and collaterals can circulate qi and blood, and respond and conduct, but when the evil-qi disturbs, they become the pathways through which the evil-qi transmits. It is reflected in pathological changes. Chapter 56 in Plain Questions says: "while the evils attack the skin, the interspace of muscle will be effected,thus, the evils go further to the collaterals, and then empty into meridians, and finally arrive at the zang-fu viscera. " This states that the meridians are the pathways whereby exogenous-evil attacks from the skin and muscle interspace to the five-zang and six-fu viscera. Because the viscera communicate through meridians and collaterals, meridians and collaterals can be the routes of unhealthy pathological changes among the viscera. For example, the Liver Meridian of the Foot-Jueyin curves around the stomach and fills into the lung, the liver disease can affect the stomach and lung; the Kidney Meridian of Foot-Shaoyin enters into the lung and connects with the heart, so the excessive water due to kidney-deficieny can attack the heart and lung. Because interior-exteriorly related meridians pertain to or connect with the same viscera, interiorly-exteriorly zang-viscera and fu-viscera are inter-influenced in pathology.For example,the heart-fire may extend down to the small intestine,the excessive heat of the large intestine and the obstruction of fu-viscera can lead to a dysfunction of lung-qi marked by asthma, cough, and stiffness in the chest. The meridians and collaterals are the routes of interaction of pathological changes arising not only from the exterior to the interior, or between the viscera, but also between the viscera and the tissues of the body surface. Through the conduction of meridians and collaterals, internal visceral diseases can be reflected on the body's surface, manifested at special positions or corresponding orifices. For example, stagnation of liver-qi with distention and pain in both hypochondriac regions and lower abdomen is due to the Liver Meridian of the Foo-Jueyin. The FootJueyin extends to the lower abdomen and spreads through the hypochondriac region. True heart pain (angina pectoris) manifests not only from the pain on the anterior part of the heart, but also from the radiating pain extending to the ulnar border in the interior side of the upper extremities. This is because the Heart Meridian of Hand-Shaoyin travels along this region. Other examples are swelling and pain in the gum due to stomach fire, and red eyes due to a flaring up of liverfire. All of those are the reflections of the meridian conduction. 2. Guiding the Diagnosis and Treatment of Diseases 1) Directing the Diagnosis of Diseases Because meridians and collaterals have fixed courses of extension in the body, and a fixed connection with the viscera, the symptoms and signs of viscera disease are easily manifested. In clinical practice, the meridian system can be the foundation of diagnosis according to the positions of symptoms, and used in combination with the meridian distributions and their related viscera. For example, pain in both hypochondriac regions is mainly due to liver and gallbladder diseases; while pain in the supraclavicutar fossa is usually caused by lung diseases. Headaches are another example. The pain in the forehead is related to the Yangming Meridian, pain in both lateral sides with Shaoyang Meridian,pain in the occipital region and nape with Taiyang Meridan, pain in vertex with Jueyin Meridian. The diagnosis of the six meridian syndromes in the Treatise on Cold Attacks is accomplished through use of the syndrome differentiation system developed from meridian theory. In addition, it is helpful to diagnose pressure pain, and the tubercular or rectangular reactive substances in places the meridians pass or where the meridian-qi gathers at some acupoints. It is helpful as well to diagnose morphological changes in the local areas of skin. An example of this diagnosis is the disorder of the lung-viscus. When it is not functioning properly, tubes in the Feishu acupoint area, and pressure pain in the Zhongfu acupoint area can occur. Another example is that pressure pain in the Lanwei extra-point will appear in patients with appendicitis. Abnormal changes in Pishu acupoint usually appear in chronic indigestion. Just as Chapter 73 in the Spirit Pivot says: "The pain can be diagnosed by observing the left parts, the right parts, the upper parts and lower parts of the body, as well as its nature of cold or warm. Then the meridian it attaches to can be decided. " This reiterates that the meridians are of great significance in clinical diagnosis. 2) Guiding the Treatment The meridian theory is broadly applied in clinical treatment, and is of great guidint significance, especially regarding the therapies of acupuncture, moxibustion, massage and Chinese herbs. The therapy of acupuncture and massage use points from local spots near the affected area, or use distant points along the meridians length in order to regulate the functiona activities of qi and blood of the meridians, thus good therapeutic effect is achieved. How ever, the point-taking must be determined through the guidelines of the meridian theory Through these guidelines one can differentiate and decide which meridian the disease treatable form and then choose the points based on the distributions and communicating ranges of the meridians. This is called "taking the points according to the meridians. " Herbal therapy also relies on the meridian theory. The herbs take effect through the channelling function of the meridians, which deliver the herbs to the affected part. Based on long-term clinical practice, ancient doctors formed a new theory called "meridian tropism of herbs. " This involved the specific selectivity of herbs geared toward one of the meridians. The famous doctors Zhang Jiegu and Li Gao in the Jin and Yuan Dynasties also founded the theory called the "meridian guiding action," based on the meridian theory. The headache, for example, belonging to the Taiyang Meridian, can be treated with the Notopterygium Root, which belongs to the Yangming Meridian and by the Baburian Angelica Root, which belongs to the Shaoyang Meridian and lastly by the Bupleurum Root. These three herbs not only pertain to the Taiyang, Yangming, Shaoyang Meridians of the hand and foot, but also guide other herbs through the above meridians in order to achieve better therapeutic effect. Additionally, widespread applied acupuncture anesthesia, ear acupuncture, electric acupuncture, catgut embodiment in acupoint, point-stimulation and ligation therapy are also founded and developed under the guidance of the meridian theory, which, of course,have further developed and enriched the meridian theory.
