The theory of meridians and acupoints is the basic theory of acupuncture and moxibustion therapy. The science of meridians expounds the routes that connect different parts of the body based on the clinical application of acupoints while the science of acupoints elucidates the relation between the viscera and the meridians in light of the theory of meridians.
Meridians and acupoints are one of the essential parts demonstrating the organic wholeness in TCM. The theory of meridians, the theory of viscera and the theory of qi, blood and body fluids constitute the theoretic base of TCM and run through the physiology, pathology, diagnosis and treatment in TCM.
General introduction to meridians
Meridians refer to the routes that transport qi and blood, regulate yin and yang, connect the zang- organs with the fu-organs, associate the external with the internal as well as the upper with the lower.
Meridians include both meridians and collaterals. Meridians refer to the longitudinal trunk parts of the meridian system, while collaterals refer to the branches of meridians. Collaterals can be further divided into sub-collaterals. The shallow collaterals are called superficial collaterals which distribute all over the body. In this way meridians and collaterals form a network connecting all parts of the body, including the viscera, five sensory organs, nine orifices, four limbs and skeleton, into an organic whole.
Meridians not only connect all parts of the body, but also coordinate their functions. By means of regulating their own conditions of qi and blood, the meridians influence the states of the viscera and regulate the physiological activities between the zang-organs, the zang and fu organs. the viscera and five sensory organs and nine orifices as well as the four limbs and skeleton to coordinate the functional activities of different parts of the body. Under morbid conditions, the meridians also influence various complicated pathological changes. The basic tenets of acupuncture and moxibustion in treating disease lie in their regulating functions through activating meridian qi to adjust tile states of the viscera.
Composition of meridian system
The system of meridians is mainly composed of the twelve regular meridians, twelve meridian branches, fifteen collaterals, twelve meridian tendons, twelve skin areas and eight extraordinary vessels (see Table 1-1).
The twelve meridians are the trunk parts of the meridian system and "are connected with the viscera internally and limbs and skeleton externally" to transport qi and blood to the viscera, limbs and skeleton. The twelve meridian branches are the branches of the twelve meridians to reinforce the connection between the zang and fu organs externally and internally related and the meridians distributing over the head and face in external and internal relation. The fifteen collaterals stem from the twelve meridians and the conception and governor vessels as well as the spleen for reinforcement of the connection of the meridians with internal and external relationship on the four limbs as well as the association of the anterior, posterior and lateral parts of the trunk of the body. The twelve meridian tendons stem from the twelve meridians for nourishing and governing the musculature and joints as well as for reinforcing the connection with the three yin meridians and three yang meridians at the same side. The twelve skin areas refer to the collaterals stemming from the twelve meridians and distributing over the skin areas. The system of the twelve meridians (excluding the collaterals of the conception and governor vessels as well as the major collateral of the spleen) extends with the distribution of the trunk parts of the twelve meridians and is the base for the twelve meridians "to transport qi and blood, nourish yin and yang, moisten tendons and bones as well as smooth the joints". The eight extraordinary vessels distribute among the twelve meridians and function to connect and regulate qi and blood in the twelve meridians. So the twelve meridians form the core of the meridian system and the other parts in the meridian system function to connect, replenish and regulate the twelve meridians.
Distribution of meridian system
The twelve meridians
The twelve meridians are the main part of the meridian system and are also known as "the twelve regular meridians" including three yin meridians of the hand, three yang meridians of the hand, three yin meridians of the foot and three yang meridians of the foot.
Distribution on the surface of the body
The twelve meridians distribute in symmetry on the face, head, trunk and limbs.
Four limbs： The yin meridians distribute along the inner-side of the four limbs, yang meridians on the lateral side of the four limbs. According to yin and yang, taiyin and yangming meridians distribute along the anterior side, shaoyin and taiyang along the posterior side, and jueyin and shaoyang along the middle side. Among these meridians, only jueyin meridian of the foot turns and converges with others in distribution. It runs anterior to the taiyin meridian of the foot 8 cun down to the medial malleolus. From the region 8 cun above the medial malleolus, it converges with taiyin meridian and runs between the taiyin and shaoyin meridians.
Trunk： The six meridians of the foot distribute in the way mentioned above. The only difference is that they pertain to either yin or yang according to the inner side and lateral side of the trunk. The three yang meridians of the foot distribute the surface of the trunk, yangming on the front, taiyang on the back and shaoyang on the lateral side, while the three yin meridians of the foot run in the interior part corresponding to the yang meridians that they are internally and externally related to. Among the six meridians of the hand, the three yang meridians all run over the shoulder to the neck while the three yin meridians all come out of the chest from the armpit.
Head and face： The six yang meridians of the hand and foot all reach the head and face to connect with the five sense organs. That is why it is said '" the head is the，convergence of all yang meridians". All the six yin meridians run deep in the head and neck to connect with the throat, tongue and eyes.
Association of the twelve meridians with the viscera
As to its rule, the association of the twelve meridians with the viscera is mainly demonstrated as "pertaining and connection". Yin meridians pertain to the zang organs and connect with the fu organs, while yang meridians pertain to the fu organs and connect with the zang organs. Besides the regular "pertaining and connection", the taiyang meridians of the hand and the foot in the six yang meridians also associate with the stomach and the brain; the six yin meridians usually associate with the other zang and fu organs. The following table is a thorough demonstration of such relations among the meridians.
Table1-2 Association of the twelve meridians with the viscera
Viscera pertaining to and connecting with
Three yin meridians of the hand
Lung,large intestine;Heart small intestine; Pericardium, triple energizer
Stomach and middle energizer Lung
Three yin meridians of the foot
Heart, Liver, lung, heart,Lung, stomach
Three yang meridians of the hand
Large intestine, lung; Small intestine, heart
Triple energizer, pericardium
Three yang meridians of the foot
Running direction, circulation and convergent principle of the twelve meridians
Running direction: Qi and blood in the twelve meridians flow in the same direction according to the distinction of three yin meridians of the hand and foot as well as three yang meridians of the hand and foot. Such a running direction is described in Lingshu (Spiritual Pivot ) as "The three yin meridians of the hand run from the chest to the hand; the three yang meridians run from the hand to the head; the three yang meridians of the foot run from the head to the foot; the three yin meridians run from the foot to the abdomen. "
Circulation: The twelve meridians form a cycle of qi and blood circulatory system with their regular and adverse circulatory directions. The circulatory order is demonstrated in the following table.
Table1-3 The flowing order of the twelve meridians
Taiyin and yangming Lung meridian of hand-taiyin→Large intestine meridian of
meridians Lung Of hand hand-yangming
-front Spleen meridian of foot-taiyin←Stomach meridian of foot-yangming
Shaoyin and taiyang Heart meridian of hand-shaoyin→Small intestine meridian
Meridians of hand and of heart-taiyang
-back Kidney meridian of foot-shaoyin←Bladder of foot-taiyang
Jueyin and shaoyang Pericardium meridian of hand-jueyin→Triple energizer
meridians of hand and meridian of hand-shaoyao
-middle Liver meridian of foot-jueyin←Gallbladder meridian of foot-shaoyao
Convergent principle：The circulatory order shows that the first fou meridians of taiyin and yangming of the hand and foot distribute along the anterior border of the body,the middle four meridians of shaoyin and taiyang of the hand and foot distribute along the posterior border of the body, the last four meridians of jueyin and shaoyang of the hand and foot distribute along the side or centre of the body. In this way qi and blood circulate in the twelve meridians for actually three cycles. The convergent way in each cycle follows the order of yin and yang meridians in external and internal relation as well as the yang meridians with the same name. According to such a convergent way and in light of the circulatory direction of the meridians, it is obvious that the twelve meridians converge with the following principle, the yin and yang meridians in external and internal relationship converge over the end of the four limbs; the yang meridians with the same name converge over the head and face; the yin meridians and yang meridians (in a cycle-like connection) converge over the chest.
The running direction, circulation and convergence are interrelated and reflect the circulatory order of qi and blood in the twelve meridians from different angles.
External and internal relation
External and internal relation, an important interrelation among the twelve meridians similar to that of the relation between zang organs and fu organs, refers to the correspondence of the three yin and three yang meridians. Such an external and internal relation among the twelve meridians, apart from the convergence of the yin and yang meridians in internal and external relation at the end of the four limbs as well as the regular "pertaining and connection" with the viscera over the trunk, further strengthens such a relation through meridian branches and collaterals. The meridian branches reinforce the relation with the organs in external and internal relation by means of "entering" and reinforce the relation of the meridians in external and internal relation on the head and face. The collaterals of the twelve meridians intensify the relation of the meridians in external and internal relation on the four limbs by means of forking into the meridians in external and internal relation.
The meridian branches of the twelve meridians
The meridian branches of the twelve meridians stem from the twelve meridians,run deep into the trunk, associate with the viscera and the branches of the meridians in external and internal relation. The meridian branches are actually the regular meridians that run along other routes. As to the nature, the meridian branches stemming from the twelve meridians pertain to the aspect of the twelve meridians. In distribution, the meridian branches run deep into the body, associate with the meridians in external and internal relation, indicating that the distribution of the meridian branches is centripetal.
The running of the branches of the twelve meridians is marked by "stemming,entering, Outthrusting and combination".
"Stemming" means that the meridian branches stem from the areas below the knees and elbows,usually the meridian branches run parallel to or together with the meridians in external and internal relation; "entering" means that the meridian branches enter the body and usually associate with the viscera in external and internal relation, the branches of the three yang meridians of the foot also associate with the heart; "outthrusting" means that the meridian branches come out to run in the superficial areas over the head and neck; "combination" means that the branches of the yin meridians combine with the yang meridians that they are in internal and external relation with, while the branches of the yang meridians combine with the meridians that they stem from.
In this way, the three yin and three yang meridians of the hand and foot constitute "six combinations". By means of "stemming, entering, outthrusting and combination", the branches of the twelve meridians further strengthen the meridians in external and internal relation, especially the association of the meridians with the viscera in external and internal relation. With such activities, the meridian branches also widen the distribution of the meridians, reinforces the association of the twelve meridians with the whole body, and enlarges the indication of the acupoints.
The fifteen collaterals
The fifteen collaterals is a collective term for the collaterals of the twelve meridians, the governor and conception vessels as well as the major collateral of the spleen.
The cyclical running of the twelve collaterals is composed of two parts:after stemming from the "Luo-Connecting" acupoints located below the knees and elbows, one part runs to the meridian that it is in internal and external relation with; the other part runs parallel to the meridian that it stems from and associates with certain viscera, organ and region. Collaterals are fine and numerous, making it difficult to locate and nominate. But the collaterals of the twelve meridians have definite location. They are connected with the meridians in external and internal relation on one hand, and run parallel to the meridians sharing both the properties of the meridians and collaterals on the other. That is why they are called "major collaterals". The three collaterals over the trunk of the body distribute on the front, back and side of the body.
The major collaterals of the twelve meridians further strengthen the association of the Meridians in external and internal relation below the knees and elbows. It is also marked by definite distribution, association with certain viscera and organs and improvement of the distribution of the twelve meridians. The three collaterals on the trunk of the body mainly function to infuse qi and blood in the front, back and side of the body.
Both the meridian branches and collaterals function to strengthen the association of the Meridians in external and internal relation. The difference is that the Meridian branches mainly strengthen the association of the viscera in external and internal relation as well as the association of the meridians in external and internal relation on the head and face; while the collaterals mainly reinforce the association of the meridians in external and internal relation below the knees and elbows.
The tendons of the twelve meridians
The tendons of the twelve meridians refer to the areas where qi from the twelve meridians accumulates and are the regions where the twelve meridians are connected with the musculature and joints.
The distribution of the twelve meridian tendons agree with the projection of the meridians that they are connect-ed with on the body surface, especially on the four limbs. The function of the meridian tendons is to nourish and govern the musculature and joints to maintain the normal activities of the body and strengthen the relation of the twelve meridians with the three yin and three yang meridians on the same side.
The twelve skin areas
The skin areas, the regions where the twelve meridians distribute on the skin, are the regions where the meridian qi effuse over the skin and the functional activities of the twelve meridians are reflected on the body surface.
The distribution of the skin areas follows the distribution of the twelve meridians on the body surface.
The skin areas govern closure and opening and are the pivot responsible for the association of the body with the nature. The skin areas regulate the closing and opening states of the muscular interstices and the functions of the viscera in response to the outward stimulation so as to enable the body to be in harmony with the nature. Such a function is closely related to the functions of defensive qi and the lung. That is why skin areas are regarded as the defensive screen of the body. Under path-ological conditions, the skin areas may act as the routes to transmit pathogenic factors inside and reflect the pathological conditions of the viscera and meridians. Clinical diagnosis and treatment of disease according to the examination of the external manifestations is actually done in light of the the-
ory of skin areas.
The eight extraordinary vessels
The eight extraordinary vessels is a collective term for the governor vessel, conception vessel, thoroughfare vessel, belt vessel, yin link vessel, yang link vessel, yin heel vessel and yang heel vessel.
Compared with the twelve meridians, there is no external and internal relation among the eight extraordinary vessels. In terms of visceral association, the eight extraordinary vessels are in close relation with the extraordinary fu organs. In terms of the distribution, they do not have their own distributing routes and just run around among the twelve meridians except the governor and conception vessels. In terms of the acupoints, they do not have their own specific acupoints except the governor and conception vessels. In terms of the functions, they do not transport qi and blood like that of the twelve meridians, just accumulate and regulate qi and blood in the twelve regular meridians.
The functions of the eight extraordinary vessels are reflected in two aspects. One is to associate the twelve meridians to command qi and blood in certain meridians as well as to regulate yin and yang. The other is to accumulate, effuse and regulate qi and blood in the twelve meridians. "To accumulate" means that the extraordinary vessels can store up qi and blood in the twelve meridians when they are superabundant. "To effuse" means that the extraordinary vessels can provide qi and blood in case of need during the acti,Aty of the body or insufficiency of qi and blood in the twelve meridians to regulate the conditions of qi and blood as well as yin and yang related to the twelve meridians.