Channels & Collaterals
Channels & Collaterals
Channels and collaterals are a significant part of human tissues and structure. Channel and collateral theory is an important part of TCM , and combines basic theories such as yin-yang and five elements theory , visceral manifestation theory , qi-blood-fluid theory. Therefore , channel and collateral theory completely reflects TCM’s basic views on human physiology and pathology.
In the past , doctors repeatedly tested theories based on their observations of physiological and pathological phenomena. From this , they drew conclusions that were gradually purified and developed into the academic theory known as the theory of channels and collaterals. This is not only the theoretical basis of acupuncture , massage and qigong , but is of significance in guiding clinical diagnosis and treatment. Just as stated in the chapter “Channels and Collaterals” in the Spiritual Pivot (Lingshu) ,“The channels are important for determining life and death, treating various diseases and regulating deficiency and excess. Hence it must be thoroughly understood.”
The Concept of Channels and Collaterals
The channels and collaterals are special tissues, structures and limbs are connecting systems through which qi and blood circulate ,and through which the viscera and limbs are connected. The channels and collaterals allow the upper-exterior portions of the body to communicate ; adjusting the functional activities of all portions of the body.
Channels and collaterals are the general terms referring to the channel vessels and collateral vessels.The chapter of Start – stop in ELementary Medicine (Yixue Rumen ) states that “the channel means pathway, while the branches separating from the channels are called collaterals.” This means that the channels from a trunk, while the collaterals represent the branches. Most of the channels run through the deep portions of the body, while their collaterals go to shallower portions, some of which are exposed on the body. As the chapter of Channels and Collaterals in Spiritual pivot states, “The twelve regular channels run deeply in the boundary between muscles, and interiorly within the body…The collaterals run closer to the surface of the body, and are more easily seen. ”Channels run in straight fixed courses, while collaterals crisscross in the body, forming a network to link together the viscera, organs, orifices, skins, muscles, tendons and bones into an organic whole, thus guaranteeing the normal and vital movement of the human body.
The Composition of Channel and Collateral System
The channel and collateral system consists of Channels, Collaterals and other Affiliated Portions.
Classification of the channel and collateral system
| The Channel-Collateral System | The Channels | Twelve Regular Channels | Twelve channels regularly running inside the body. The main part of the channel-collateral system |
| Eight Extraordinary Channels | Eight important channels besides the twelve regular channels | ||
| Twelve Channels Divergent | Twelve important channels branching out from the twelve channels | ||
| The Collaterals | The Divergent Collaterals | Larger and major collaterals | |
| The Minute Collaterals | Tiny and small collaterals | ||
| The Superficial Collaterals | The collaterals distributed on the body surface | ||
| The Affiliated Portion | The Channels Sinews | The system of the twelve channels connecting tendons-muscles | |
| The Cutaneous Regions | The sites in the body surface reflecting the twelve channels and the collaterals |
Channels
Channels are the main trunk of the channel-collateral system. They can be divided into two types : regular channels and extraordinary channels. In addition , channel divergences are also included in the channnel-collateral system.
There are twelve regular channels ,including the three yin channels of the hands and the feet , and the three yang channels of the hands and the feet . These are generally termed “ the twelve regular channels. ”They are the main pathways in which qi and blood circulate. The twelve regular channels originate and terminate in certain areas. They also have a specific course and a sequence of circulation. There is a method to their distribution as they pass over and through the trunk and limbs and they connect with the viscera directly in the body’s interior. It is stated in the chapter of Discussion on Sea in Spiritual Pivot , “The twelve channels are internally related to the zang-viscera and fu-viscera , and externally connected with the limbs and joints .”
In addition to the twelve regular channels , the extraordinary channels are also important channels. There are eight channels that , collectively , are termed “the extraordinary channels.”These are the Du ( Governor Channel ) , Ren ( Conception Channel ) ,Chong , Dai , Yinqiao , Yangqiao , Yinwei , and Yangwei. They have the functions to govern , communicate , and regular qi and blood within the twelve channels. The book General Collection for Holly Relief (sheng Ji zong Lu ) states ,“Channels can be divided into the extra and the regular , the twelve channels belong to the regular, and the eight channels are different from the regular , as they go along additional courses. The qi and blood of the human body run along the twelve regular channels and flows into the extraordinary channels while the regular ones are full. ” The twelve divergent channels are categorized as channels because their running paths are deep and long.
Collaterals
Collaterals are branches of channels. Their pathways are shallower than the channels. Collaterals are classified as divergent , superficial , or minute. The divergent collaterals are larger and are considered major collaterals. The superficial collaterals run superficially and often appear at the surface. The minute collaterals are the tiniest collaterals. Except for divergent collaterals , most have no certain pathway. The branches of the collaterals gradually become smaller , turning into minute collaterals. These extend from threadiness to facet , thus closely connecting all parts of the tissues of the human body.
Affiliated Portions
The sinew channels and cutaneous regions are the affiliated portions in the tendons , muscle and the skin. They are closely connected to the channels and collaterals. Channel-Collateral theory holds that the sinew channels are the system whereby the channel-qi concentrates , accumulates , distributes , and connects with the tendons , muscles and joints. Their function is to connect limbs and bones , as well as control joint movements. The skin of the whole body represent the superficial regions of the twelve channels and collaterals. Therefore ,the skin throughout the entire body is divided into twelve parts that respectively belong to each of the twelve channels.
Twelve Regular Channels
Nomenclature and Classification
The twelve regular channels make up the core part of the channel-collateral system. The extraordinary channels , the divergent channels , and the collaterals in the channel-collateral system all branch from the twelve regular channels. They synergistically communicate and coordinate with each other.
The twelve regular channels run bilaterally and symmetrically throughout the body. They run through the medial or lateral aspects of the upper or lower extremities, and connect with their respective zang-viscera or fu-viscera. Thus, the name of each channel of the twelve regular channels includes three parts: yin or yang, hand or foot , and zang-viscera or fu-viscera.
The channels of the hand run along the upper limbs ,while the channels of feet run along the lower limbs. Yin channels run along the medial aspect of the four extremities and pertain to the zang-viscera , while the yang channels travel along the lateral aspect of the four limbs and pertain to fu-viscera. The three yin channels of the hand and foot include Taiyin , Shaoyin and Jueyin. The three yin channels of the hand and foot include Taiyang , Shaoyang and Yangming. These terms are based on the theory of growth and deline of the yin-qi and yang-qi in Huangdi’s Inner Classic of Medicine. The following table expains the name given to each of the twelve channels.
The Name of Twelve Regular Channels
| Hand-Foot
Yin Channel | Hand Yin Channel | Lung Channel of Taiyin | Pericardium Channel of Jueyin | Heart Channel of Shaoyin |
| Foot Yin Channels | Spleen Channel of Taiyin | Liver Channel of Jueyin | Kidney Channel of Shaoyin | |
| Hand-Foot
Yang Channel | Hand Yang Channels | Large Intestine of Yangming | Triple-Jiao Channel of Shaoyang | Small Intestine Channel of Taiyang |
| Foot Yang Channels | Stomach Channel of Yangming | Gallbaldder Channel of Shaoyang | Bladder Channel of Taiyang |
Pathways and Distribution of Channels and Cllaterals
The twelve regular channels run bilaterally and symmetrically throughout the body.Each channel follows a specific course of distribution and has specific connections in the body.
1. Regularity in Course and Connection
The chapter of Abnormality , Normality ,Obesity and Emaciation in the Spiritual Pivot states , “The three yin channels of the hand travel from the viscera to the hand ; the three yang channels of the hand run from the hand to the head ; the three yang channels of the hand run from the hand to the head ; the three yang channels of the foot go from the head to the foot ; the three yin channels of the foot run from the foot to the abdomen.” For example , the three yin channels of the hand travel from the chest to the ends of the fingers , then connect with the three yang channels of the hand ; the three yang channels of the hand run from the end of the fingers to the head and the face , then communicate with three yang channels of the foot ; the three yang channels of the foot go from the face and the head down to the end of the toes , then connect with three yin channels of the foot ; the three yin channels of the foot start from the toes and go up to the abdomen and chest to connect with three yin channels of the hand .Thus , forming “ a circulative pathway of inter-connection of yin and yang channels which travel in the body endlessly like a cycle. ”( Chapter of the Production and Convergence of Nutrient-qi and Defensive-qi in Spiritual Pivot )
Along the course and connections of the twelve channels , the connecting parts present with regularity. The exterior-interior related yin and yang channels connect with each other at the ends of limbs. Specifically ,the three exterior-interior related yin and the three exterior-interior yang hand channels connect at the ends of upper limbs ( fingers ). The three exterior-interior related yin and the three exterior -interior related yang channels of the foot connect at the ends of lower limbs ( toes ). The yang channels of hand and foot that share the same name connect in the head and face ; yin channels of foot and hand connect on the thorax (Fig. 1).
2. Regularity in Distribution
The twelve channels on the body surface have a certain regularity in their distribution.
2.1 In the four limbs
Yin channels distribute on the medial sides , and yang channels on the lateral sides of the limbs. The anterior border is supplied by the Taiyin and Yangming Channels ; the midline by the Jueyin and Shaoyang Channnels ; the posterior border by the Shaoyin and Taiyang Channels (Tab. 5-1 ). On the medial side of lower limb , 8 cun below the medial malleolus , the channel distribution deviates from the patterns stated above. Instead , the Jueyin channel of foot runs in the anterior aspect , and the Taiyin channel of spleen in the middle. The two channels cross at the region of 8 cun above the medial malleolus and revert to the normal distribution.
Regular distribution of the twelve channels in the four limbs
| Yin Channel (zang – viscus) | Running Rout (yin in medial side, yang channel in the lateral side) | Yang Channel (fu – viscus) | |
| Lung Channel of Hand – Taiyin | Upper limb | Anterior line | Large Intestine of Hand – Yangming |
| Pericardium Channel of Hand -Jueyin | Middle line | Triple – jiao channel of Hand – Taiyang | |
| Heat Channel of Hand – Shaoyin | Posterior line | Small Intestine Channel of Hand – Taiyang | |
| Spleen Channel of Foot- Taiyin | Lower limb | Anterior line | Stomach Channel of Foot – yangming |
| Liver Channel of Foot – Jueyin | Middle line | Callbladder Channel of Foot -Shaoyang | |
| Kidney Channel of Foot – Shaoyin | Posterior line | Bladder Channel of Foot – Taiyang | |
The Liver Channel runs along the anterior – line on the lower part of the leg and dorsum of the foot. The spleen channel runs along the midline , and these two channels cross each other 8 cun above the medial malleolus. At this point , the Spleen Channel runs along the anterior – line , while the Liver Channel runs along the midline.
2.2 On the head and face
“The head is the confluence of yang channels.” The hand and the foot yang channels are distributed on the head and the face.Among them , the Hand – Foot yangming Channels are distributed on the face and the forehead ; the Hand – Foot Shaoyang Channels travel along lateral aspect of the head ; and the Hand – Foot Taiyang Channels run along the cheek , the vertex , and the back of the head.
2.3 On the trunk of the body
The twelve channels all connect with the trunk in their running course and distribution. Their distribution regularity is as follows ; the three yin channels of the hand all emerge from the area below the axilla , whereas three yin channels of the foot run through the abdominal regions. Passing through the abdominal region , the Foot Shaoyin Kidney Channel is the first channel moving outwards from the midline. Moving laterally is the Foot Yangming Stomach Channel followed by the Foot Taiyin Spleen Channel and the Foot Jueyin Liver Channel.
A noteworthy point is that the twelve channels run symmetrically on the left and right sides of the body on the trunk , head ,face and limbs. This means that each side is comprised of twelve channels. Each yin channel and yang channel have an exteriorly – interiorly related respectively affiliate and connect to the exteriorly – interiorly related viscera. At the same time , they run along corresponding parts on the interior of the four limbs.
Interior – Exterior Relationships
The three yin and three yang channels of the hand and foot comprise six pairs of channels of “exterior – interior correspondence” through many communication approaches.
Exterior – Interior Correspondence
| Exterior | Hand Yangming | Hand Shaoyang | Hand Taiyang | Foot Yangming | Foot Shaoyang | Foot Taiyang |
| Interior | Hand Taiyiin | Hand Jueyin | Hand Shaoyin | Hand Taiyin | Foot Jueyin | Foot Shaoyin |
The two interior – exterior related channels connect at the end of the four extremities and respectively communicate with the extriorly – interiorly connected viscera. For example , the Foot Taiyang Channel pertains to the urinary bladder and communicates with the kidney ; the Foot Shaoyin Channel pertains to the kidney and communicates with the urinary bladder. They communicate with channel divergences and divergent collaterals , forming many kinds of communicative relationships among the exterior – interior channels. The sixty – seventh Problem in the Original Meaning of the “Classic on Medical Problems ” (Nanjing Benyi ) states that “ the channels and collaterals are where qi communicates and fills.” The exterior – interior relationships among the channels are basis to form the close connection of zang – fu viscera.
Order of Cyclical Flow
The twelve channels are the main passageways for the circulation of qi and blood and are distributed over the interior and exterior of the body.The qi and blood circulate endlessly in the channels. Beginning with the Lung Channel of the Hang Taiyin ,and ending with the Liver Channel of the Foot Jueyin in a particular order , this process then returns once more to the Lung Channel. The inter – connection of the beginning and ending – spot is similar to a cycle , with the order of this flow begin as follows (Fig. 2):
Running Routes of Twelve Channels
1. Lung Channel of Hand Taiyin
The channel originates in the middle – jiao , running downward to connect with the large intestine. Winding back , it runs along the two openings of the stomach ( the lower opening is the pylorus and the upper one is the cardia ) and passes through the diaphragm to then enter the lung , its belonging viscus. It then ascends to the throat and transversely runs to the superolateral aspect of the chest ( zhongfu , LU 1 ) . The channel comes out from the axilla , descends along the anterior border of the flexor aspect of the upper limb and passes through the cubital fossa to enter cunkou { the radial artery at the wrist for pulse feeling ). It then arrives at the thenar eminence and reaches the radial side of the tip of the thumb ( Shaoshang , LU 11 ) .
The branch : Emerging from the proximal part of the wrist ( Lieque , LU 7 ) , it runs along the dorsal aspect of the palm to the radial side of the tip of the index finger ( Shangyang , LI. 1 )where it links the large intestine channel of hand Yangming (Fig. 3).
2. Large Intestine Channel of Hand Yangming
The channel originates at the radial side of the tip of the index finger ( Shangyang , LI 1).Passing through the dorsum of the hand , it runs upward along the anterior border of the extensor aspect of the upper limb and arrives at the anterior aspect of the shoulder joint. It then runs backward to the site beneath the spinous process of the seventh cervical vertebra ( Dazhui , GV 14 ) ,and runs forward and downward to the supraclavicular fossa ( Quepen , ST 12 ). From there , it enters the thoracic cavity to connect with the lung , and further passes through the diaphragm to terminate at the large intestine , its belonging viscus.
The breach : Emerging from Quepen ( ST 12 ) , it runs upwards through the neck to the cheek , and enters the gums of the lower teeth. Then returning and running by the mouth , it crosses the opposite channel at the philtrum , and runs to the site beside the opposite wing of the nose ( Yingxiang , LI 20 ) , where it connects the stomach channel of foot Yangming (Fig. 4).
3. The Stomach Channel of Foot Yangming
It originates from the site beside the wing of the nose ( Yingxiang LI 20 ) and ascends along the brighe to the root of the nose where the left and the right channels meet. It then runs laterally to the inner cantus where it meets withe the bladder channel of foot Taiyang. The channel then runs downward along the lateral side of the bridge of the nose to enter the upper gums of the teeth. Returning , it runs by the mouth to curve around the lips and then meets the opposite channel at the mentolabial groove ( changjiang , GV 24 ). Turning back , it runs along the posterior – inferior border of the mandible to the site anterior to the angle of the mandible ( Daying , ST 5 ). It then ascends in front of the ear , passing through Shangguan point ( GB 3 ) and runs along the anterior hairline to reach the forehead.
Branch 1 : Emerging in front of Dying acupiont , it runs downward to Renying acupoint ( ST 9 ). Along the throat , it runs backward and downward to Dazhui (GV 14 0. Turning back , it runs forward to Quepen ( ST 12 ) and then runs deep into the cavity of the body , descending through the diaphragm and entering the stomach , its belonging viscus , and connecting with the spleen.
The straight portion : Starting from Quepen ( ST 12 ) ,it runs downward along the midclavicular line and by the umbilicus to Qichong , located at the superior to inguinal groove.
Branch 2 : Emerging from the lower opening of the stomach ( pylorus ) , it descends along the inside of the abdomen to Qichong , where it joins the straight portion. Then , it runs downward along the anterior aspect of the thigh towards the knee. Descending along the anterior border of the lateral aspect of the tibia it arrives at dorsum of the foot. It then enters the lateral side of the tip of the 2nd toe (Lidui ST 45 ).
Branch 3 : Emerging from the site 3cun below the knee ( Zusanli , ST 36 ) ,it descends and enters the lateral side of the tip of the middle toe.
Branch 4 : Arising from Chongyang ( ST 42 ) it runs forward to the medial side of the tip of the big toe ( Yinbai , SP 1 ) , where it links the spleen channel of foot Taiyin (Fig. 5).
4. The Spleen Channel of Foot Taiyin
The channel originates from the medial side of the tip of the big toe ( Yinbai , SP 1 ). It runs along the junction of the red and the white skin on the medial aspect of the foot. From there ,it ascends along the anterior border of the medial malleolus and along the mid – line of the medial aspect of the leg to the site 8cun above the medial malleolus. At this point , it crosses the liver channel of the foot Jueyin and continues in front of this channel. It ascends along the anterior border of the medial aspect of the thigh , enters the abdomen , arrives at the spleen , its belonging viscus , and connects with the stomach. Running upward through the diaphragm , it runs alongside the esophagus , reaches the root of the tongue , and scatters its collaterals over the lower surface of the tongue.
The branch : Arising from the stomach , it ascends through the diaphragm and enters the heart , linking with the heart channel of hand Shaoyin (Fig. 6).
5. The Heart Channel of Hand Shaoyin
It originates from the heart , enters the heart connector , runs downward through the diaphragm and connects with the small intestine.
The branch : Coming out from the heart connector , it runs upward alongside the esophagus to connect with the eye connectors.
The straight portion : Emerging from the heart connector , the channel runs through the lung. It then descends and runs superficially from the axilla ( Jiquan , HT 1 ). Along the posterior border of the medial aspect the upper limb , it runs and passes through the cubital fossa . Near the styloid process of the ulna , it enters the palm. Then it runs along the radial side of the little finger to its tip ( Shaochong , HT 9) and links the small intestine channel of the hand Taiyang (Fig. 7).
6. The Small Intestine Channel of Hand Taiyang
The channel originates at the tip of the ulnar side of the little finger ( Shaoze, SP 1 ). Following the posterior border of lateral aspect of the dorsum and upper limbs, it runs and passes the cubital region, reaching the region posterior to the shoulder joint. After winding through the scapular region, it reaches the superior part of the shoulder ( Dazhui, GV 14 ). It then runs forward to Quepen ( ST 12 ), enters the body cavity to connect with the heart, descends along the esophagus, passes through the diaphragm, reaches the stomach ,and finally enters the small intestine, its belonging viscus.
Branch1 : Emerging from Quepen ( ST 12 ), it ascends along the neck to the cheek. Arriving at the outer canthus, it then runs back and enters the ear ( Tinggong, SP 19 ).
Branch2 : Emerging from the cheek, it runs up to the infraorbital region, then reaches the inner canthus ( Jingming, BL 1 ) to link with the bladder channel of foot Taiyang (Fig. 8).
7. The Bladder Channel of Foot Taiyang
The channel originates from the inner canthus ( Jingming, BL 1 ). Ascending to the forehead, it reaches the vertex ( Baihui, GV 20 ) and meets its opposite channel there.
Branch 1 : Arising from the vertex, it runs to the region above the ear apex.
The straight portion : Starting from the vertex, the channel runs backward to the occipital region where it enters the cranial cavity to communicate with the brain. Returning, it descends to the nape ( Tianzhu, BL 10 ), and further to Dazhui ( GV 14 ), meeting its opposite channel. It then runs down the medial aspect of the scapula at a measurement of 1.5cun lateral to the vertebral column. Arriving at the lumbar region (Shenshu, BL 23 ), it enters the body cavity via the paravertebral muscles to connect with the kidney and join its belonging viscus, the bladder.
Branch 2 : Branching out from the lumbar region, it descends alongside the vertebral column, and passes through the gluteal region. Then following the posterior aspect of the thigh, it ends at the popliteal fossa (Weizhong, BL 40).
Branch 3 : Starting at the nape ( Tianzhu, BL 10 ), it descends along the medial aspect of the scapula. From Fufen ( BL 41 ), it descends alongside the vertebral column ( 3cun ) to the region of the greater trochanter. It then runs down along the posterior aspect of the lateral side of the thigh to the popliteal fossa, where it meets the preceding branch. It further runs down and passes the musculus gastrocnemius. Passing by the posterior of the lateral malleolus, it runs along the lateral border of the dorsum of the foot and reaches the lateral side of the tip of the little toe ( Zhiyin, BL 67 ),where it links with the kidney channel of foot Shaoyin (Fig. 9).
8. Kidney Channel of Foot Shaoyin
It originates at the inferior aspect the little toe and runs obliquely through the center of the sole ( Yongquan, KL ). Emerging from the lower aspect of the tuberosity of the navicular bone, it runs behind the medial malleolus and branches out to enter the heel. Ascending along the posterior border of the medial aspect of the leg to the medial side of the popliteal fossa, it runs further upwards along the posteromedial border of the thigh to enter the vertebral column ( Changqiang, GV 1 ). Passing through the vertebral column, it enters the kidney, its belonging viscus, and connects with the bladder.
The straight portion : Starting from the kidney, it ascends and passes through the liver and diaphragm; then it enters the lung, and runs along the throat up to the tongue, ending on the two sides of it.
The branch : Arising from the lung, it connects with the heart and enters the chest to link the pericardium channel of hand Jueyin (Fig. 10).
9. The Pericardium Channel of Hand Jueyin
It ogiginatates from the inside of the chaest. Emerging, it enters its belonging viscus, the pericardium. Then, it descends through the diaphagm to connect successively with the upper, middle, and lower – jiao.
Branch 1 : Arising from the chest, it runs transversely and emerges superficially from the costal region at a point 3cun below the anterior axillary fold ( Tianchi, PC 1 ). Then, it ascends to the axilla; following the midline of the medial aspect of the upper limb, it enters the cubital fossa, passes through the wrist, and enters the palm ( Laogong, PC 8). It further runs along the radial aspect of the middle finger to its tip ( Zhongchong, PC 9 ).
Branch 2 : Coming out from the center of palm, it runs along the ulnar aspect of the ring finger to its tip ( Guanchong , TE 1 ) , and links the Triple – Jiao Channel of Hand Shaoyang (Fig. 11).
10. The Triple – Jiao Channel of Hand Shaoyang
It originates from the end of the ulnar aspect of the ring finger ( Guanchong, TE 1 ). Ascending along the ulnar aspect of the ring finger to the dorsal aspect of the wrist, it runs upward between the radius and ulna. Passing through the olecranon and along the lateral aspect of the upper arm, it reaches the shoulder region. From there it runs anterior and enters Quepen ( ST 12 ) and further scatters over and connects with the pericardium. Passing through the diaphragm, it successively enters the upper – middle and lower – jiao, its belonging viscus.
Branch 1: Arising from the pericardium, it ascends and then emerges from Quepen ( ST 12 ), and runs to the shoulder region. Meeting its opposite channel at the Dazhui ( GV 14 ), it ascends to the nape, and runs by the posterior border of the ear ( Yifeng, TE 7 ), running directly up to the region superior to the apex of the ear. It then curves downward to the cheek and arrives at the infraobital region.
Branch 2: Emerging from the retrouricular region, it enters the ear, comes out in front of the ear and passes by the area anterior to Shangguan point ( GB 3 ) to cross the preceding branch at the cheek. It further runs to the outer canthus ( Tongziliao, GB 1 ) to link with the gallbladder channel of foot Shaoyang (Fig. 12).
11. The Gallbladder Channel of Foot Shaoyang
It originates from the outer canthus ( Tongziliao, GB 1 ) and ascends to the corner of the forehead ( Hanyan, GB 14 ). The channel then turns downward to the retroauricular region ( Wangu, GB 12 ) and turns back to re – ascend through the forehead to the superior region of the eyebrow ( Yangbai, GB 14 ). Hereafter it returns and runs down to Fengchi point ( GB 20 ), descending along the neck to the shoulder where it meets its opposite channel at Dazhui (GV 14 ). After this, it finally reaches Quepen (ST 12 ).
Branch 1 : Arising from the retroauricular region, it enters the ear, comes back out, passes the preauricular region, and runs up to the posterior aspect of the outer canthus.
Branch 2 : Emerging from the outer canthus ( Tongziliao, GB 1 ), it descends to the Daying ( ST 5 ) where it meets the branch of the Triple – Jiao Channel of Hand Shaoyang at the cheek, and arrives at the infraorbital region. It then returns and runs down through the angle of the mandible to the neck; meeting the main channel at Quepen ( ST 12 ). From there it enters the body cavity, passes through the diaphragm to connect with the liver, and enters its belonging viscus, the gallbladder. Then it runs inside the hypochondriac region to the inguinal region. From there it emerges and runs superficially along the margin of the public hair and transversely runs into the Huantiao acupoint ( GB 30 ) at the hip region.
The straight portion : Starting from the Quepen ( ST 12 ），it runs downward to the axilla, further descends along the lateral aspect of the chest and through the floating ribs to Huantiao point ( GB 30 ) where it meets the preceding branch. Then it again runs downward along the lateral aspect of the thigh and the lateral side of the knee joint. Going down in front of the fibula it directly reaches the lower end of the fibula. Coming out superficially at the anterior aspect of the external malleous, finally it runs along the dorsum of the foot to the lateral aspect of the tip of the 4th toe ( Foot Qiaoyin, GB 44 ).
Branch 3 : Branching out at the dorsum of the foot ( foot – Linqi, GB 41 ), it runs anterior to the lateral aspect of the tip of the big toe. Returning, it passes through the nail and arrives at the hairy region of the big toe, where it links the Liver Channel of Foot Jueyin (Fig. 13).
12. The Liver Channel of Foot Jueyin
It originates from the dorsal hairy region of the big toe, and ascends along the dorsum of the foot to the region 1cun anterior to the medial malleolus ( Zhongfeng, LV 4 ). It then runs superior along the medial border of the tibia to a site 8cun above the medial malleolu. From here, it crosses the Spleen Channel of Foot Taiyin, runs alongside the medial side of the knee, and continues along the midline of the medial aspect of the thigh to the pubic hairy region. Curving around the external genitalia, it runs up to the lower abdomen and enters the abdominal cavity. It runs by the stomach, enters its belonging viscus, the liver, and connects with the gallbladder. After that, it ascends through the diaphragm, branching out to spread over the costal and hypochondriac region. The channel then ascends along the posterior aspect of the throat to the nasopharynx and runs up to link the eye connector. Emerging from the forehead, it runs up to the vertex where it meets Du vessel at the Baihui ( GV 20 ).
Branch 1 : Arising from the eye connector, it descends, runs along the inside of the cheek, and curves round the inner surface of the lips.
Branch 2 : Coming our of the liver, it ascends through the diaphragm and enters the lung to connect with the Lung Channel of Hand Taiyin (Fig. 14).
Eight Extraordinary Channels
The Concepts and Characteristics of Eight Extraordinary Channel (Vessels)
The eight extraordinary (extra meaning different) channels (vessels) are the eight channels that are not distributed as regularly as the twelve regular channels. They include the Du, Ren, Chong, Dai, Yinqiao, Yangqiao, Yinwei and Yangwei channels. Since the extraordinary channels ( vessels ) have different running routes and have no direct connections with the viscera, they are therefore called the “extraordinary channels (vessels) “.
Characteristics of these channels are as follows: they are not distributed as regularly as the twelve regular channels and they have no direct connection or affiliation to the viscera. However, while the extraordinary fu – viscera have certain connections with some of the zang – fu – viscera, there are no exterior – interior relations among the eight extraordinary vessel.
The Physiological Functions of Eight Extraordinary Channels (Vessels)
The eight extraordinary channels (vessels) run vertically, transversely, and crosswise among the twelve channels. The function of the eight extraordinary channels (vessels) mainly present with the following three aspects:
1. Further strengthening the communication of twelve regular channels
In the running and distributing process, the eight extraordinary channels (vessels) crisscross with some of the twelve channels so as to strengthen the communication among the twelve channels. For example, the Du Vessel “governs all the yang channels “ and meets with the six yang channels of both hand and foot at Dahui point (GV 14).
2. Regulating the qi and blood of the twelve channels
The eight extraordinary channels (vessels ) are intricately distributed. At the same time, they circulate among the twelve channels. When the qi and blood of the twelve channels becomes over abundant, it will flow into the eight extraordinary channels (vessels) for storage. When the qi and blood of the twelve channels becomes deficient, the extraordinary channels ( vessels ) will supply stored qi and blood so as to compensate, irrigate, and supply the tissues of the whole body.
3. Participating the adjustment of reproduction function and braid and marrow
Contributing to reproductive health, and the functions of the brain and marrow. The eight extraordinary channels (vessels) are closely related to the liver, kidney and urinary bladder. They play a role in the functions of menstruation, leucorrhea, fetation, and the labor of women. Thus, they participate in the reproductive function of the human body. In their running and distributing processes, they rather closely communicate with brain and marrow. The channels communicate with them both physiologically and pathologically.
The Running Routes and Functional Characteristics of Eight Extraordinary Channels (Vessels)
1. Du Vessel
1.1 Running Route
The Du Vessel originates from the interior of the womb. Descending, it emerges at the perineum. It then ascends along the inside of the spinal column to Fengfu (GV 16) at the nape. From there, it enters the cranial cavity to communicate with the brain. It further runs following the midsagittal line on the head, via the vertex, forehead, nose and upper lip, and reaches the frenulum of the upper lip (Yinjiao, GV 28). It also has branches joining the kidney and passing through the heart (Fig. 15).
1.2 Functional characteristics
Du here means governing or commanding. Therefore the functional characteristics of Du Vessel are as follows :
1.2.1 Adjusting the qi and blood of the yang channels
The Du Vessel runs along the mid – line of the back. The Du Vessel‘s qi meets the qi of the three yang channels of the hand and foot, as well as the Yangwei Vessel on numerous occasions. Due to this, it has adjusting function on the yang channels of the whole body. This is why it is also called “the sea of yang channels “.
1.2.2 Having close relations with the brain, spine and kidney
The Du Vessel runs along the inside of the spine, branches out to join the kidney, and continues upwards to the brain. The Kidney governs the storing of essence and the generating of marrow, and the brain is the sea of marrow.Due to these connections, the Du Vessel has a close relationship with the brain, marrow and the kidney.
2. Ren Vessel
2.1. Running route
The Ren Vessel originates from the interior of the womb. Descending, it emerges at the perineum. It then ascends via the mons pubis along the mid – line of the abdomen and chest to the throat. It further runs up to the mandibular region, curves round the lips, and passes through the cheek. At this point it bifurcates to arrive at the infraorbital regions (Fig. 16 )
2.2 Functional characteristics
Ren here means assuming, or undertaking. The functional characteristics of Ren Vessel are as follows:
2.2.1 Controlling the qi and blood of yin channels
The Ren Vessel runs along the anterior midline of abdomen. Its vessel qi communicates with the three yin channels of the foot and Yangwei Vessel. The channel links with the yin channels, so it has an adjusting function on the qi and blood of yin channels. Therefore, it is called “the sea of yin channels “.
2.2.2 Dominating the uterus and pregnancy
Since the Ren Vessel originates in the uterus, it is able to adjust the menses and promote the reproductive function of women. It shares a relationship with pregnacy, so it is said that “the Ren Vessel dominates the uterus and pregnancy”, and is the root of giving birth.
3. Chong Vessel
3.1 Running route
The Chong Vessel originates in the womb. Descending, it emerges at the perineum, then superficially bifurcates into three branches. One runs posterior and connects with the Du vessel, running in front of the spinal column. Another reaches the inguinal region (Qijie, ST 30), joins the kidney vessel of foot Shaoyin, ascends by the umbilicus, and spreads into the chest. It then runs up through the thraot and curves around the lips to terminate at the infraorbital region. A third branch emerges superficially at the inguinal region, runs down along the medial aspect of the thigh to the popliteal region, and further descends along the medial side of the tibia to the sole. The branch of the area posterior to the medial malleolus runs forward and obliquely passes the dorsum of the foot to enter the big toe (Fig. 17).
3.2 Functional characteristics
Chong here means vital pass. Its functional characteristics are as follows:
3.2.1 Adjusting the qi and blood of the twelve channels
The Chong Vessel runs upward to the head and downward to the foot. It is a vital pathway of qi and blood, so it is also called “ the sea of the twelve regular channels “.
3.2.2 Being the sea of blood
The Chong Vessel originates in the womb and has a close connection to female menstruation. Due to the connection with reproductive function, it is also termed “ the sea of blood “.
4. Dai Vessel
4.1 Running route
The Dai Vessel originates at the hypochondrium, runs obliquely downward to the Daimai point (GB 26), and then runs transversely around the waist and abdomen (Fig. 18).
4.2 Functional characteristics
The Dai Vessel wraps around the waist in a similar manner as a girdle. Its functional characteristics are as follows :
4.2.1 Blinding and controlling the channels running vertically
The Dai Vessel is the only vessel that runs around the waist. It runs around the waist and is able to bind all channels that run vertically.
4.2.2 Controlling the white in women
It is found by clinical observation that vaginal discharge of women has certain connection with the function of Dai vessel.
5. Yinqiao and Yangqiao Vessels
5.1 Running route
The Qiao Vessel exist as a pair on the left and right sides of the body. Both the Yinqiao and Yangqiao Vessels originate from the site inferior to the malleoli. The Yinqiao Vessel originates inferior to the medial melleolus and runs upward, via the posterior side of the medial malleolus and along the medial aspect of the chest to Quepen (ST 12). Running further upward along the area anterior to Renying (ST 9), it runs by the bright of the nose to the inner canthus and meets with the Taiyang Vessels of the hand and foot, and the Yangqiao Vessel (Fig. 19).
The Yangqiao Vessel originates inferior to the external malleolus. It runs upward via the posterior side of the external malleolus and along the posterior border 
of the fibular aspect of the thigh. Passing through the abdomen and along the posterolateral aspect of the chest, it runs upwards via the shoulder and lateral side of the neck to the angle of the mouth. Reaching the inner canthus, it meets with the Taiyang Vessels of the hand and foot, and the Yinqiao Vessel. It then further ascends through the anterior hairline, turns down to the retroauricular region, and finally meets the Gallbladder Vessel of the Foot Shaoyang at the nape (Fig. 20).
5.2 Functional characteristics
The Chinese word “qiao” means to act quickly. Their function are as follows:
5.2.1 Controlling the motion of the lower limbs
The Qiao Vessels originate from the sites inferior to the malleoli and run up along the medial and lateral sides of the limb to the head and face. They have the function to communicate the yin and yang qi of the whole body, and regulate the muscles in order to make the lower limbs forceful and nimble in motion.
5.2.2 Dominating the opening and closing of the eyelids
The Yinqiao and Yangqiao Vessels meet at the inner canthus and enter the brain. They therefore have the function of moistening the eyes and controlling the closing and opening of the eyelids.
6. Yinwei and Yangwei Vessels
6.1 Running route
The Yinwei Vessel originates from the medial side of the legs where the three yin vessels of the foot meet. It runs up along the medial side of the lower limbs to the abdomen, and then coincides with the Spleen Vessel of the Foot Taiyin. Arriving at the hypochondrium, it meets with the Liver Vessel of the Foot Jueyin. It then ascends to the thraot to meet with Ren Vessel (Fig. 21).
The Yangwei Vessel originates inferior to the external malleolus. Coinciding with the Gallbladder Vessel of Foot Shaoyang, it runs up along the lateral side of the lower limb to the posterolateral aspect of the trunk. Passing through the posterior axilla to the shoulder, it further ascends via neck and retroauricular region, and forward to the forehead. It then turns backward to the lateral side of the head and back of the nape, where it communicates with the Du Vessel (Fig. 22).
6.2 Functional of characteristics
The Chinese word “wei ‘ means maintaining and network. The Yinwei and Yangwei Vessels maintain and network the yin and yang channels of the whole body respectively.
Other Channels & Collaterals
1. Basic Concepts
The twelve channel divergences are the important branching channels arising respectively from the twelve channels. They run deep into the thoracic, in the chest, and in the abdomen and head. Since they are different from regular channels but are included in the channel system, they are called divergent regular channels, and “ channel divergence “ for short.
2. Distribution Regularity
The characteristics of the distribution of the twelve Channel Divergences can be described as “ departing, entering, exiting and combining “. Departing refers to the fact that the twelve Channel Divergences are distributed in a branching manner from certain parts of the four limbs.Tjis occurs mostly above the elbows and knees of the twelve regular channels. Entering refers to the fact that Channel Divergencs enter the deep inside of the viscera. Exiting means they finally travel outward to the face and head. Combining refers to the fact that the yin channel’s divergences combine with the yang channel’s divergences with the exterior – interior relationships. Each pair of exterior – interiorly related channels divergences are called a “ combination “, and altogether from “ six combinations “.
At the same time, the divergences of the yang channels have connections with their connected viscera. For instance, the divergences of the three yang channels of the foot pass through the heart and go up to the head; the divergences of the three yin channels of hand enter the viscera from the axilla and pass through the throat and go up the head and face.
3. Physiological Functions
The twelve channels divergences are broadly distributed. Some of the locations are where the twelve channels cannot reach. They therefore have functions of particular importance in relation to physiology, clinical treatment, etc. The main points are as follows: 1. To reinforce the connection of pair of exterior – interiorly related channels of the twelve regular channels in the body.2. To reinforce the centripetal connections of the exterior and interior of the body; and of the limbs and the trunk .3. To reinforce the connection between the twelve concerning the twelve regular channels and the area of the face and head. 4. To enlarge the scope of the indications concerning the twelve regular channels. 5.To strengthen the relations of the three yin and yang channels of the foot withe heart.
1. Basic Concept
Divergent collaterals are the larger ones in the collateral. Together, the twelve main channels and the Ren and Du vessels respectively create one branch. Additionally, there is a large branch from the spleen channel to account for a total of fifteen channels, known collectively as the “ fifteen divergent collaterals. “ If the larger collateral of the stomach channels is counted, they are called “ sixteen divergent cllaterals “.
2. Distribution Regularly
Most of the divergent collaterals are oblique branches. They have a certain regularity in their distribution. On the four limbs, the divergent collaterals of the twelve channels branch out respectively from the proper channels at the sites below the elblow or knee. The collaterals of yin – channels join the yang – channels exterior – interiorly connected with them; and the collateals of yang – channels join the yin – channels exterior – interiorly connected with them. On the trunk, three collaterals are distributed on the anterior, posterior and lateral side of the body. The divergence of the Ren vessel spreads over the abdomen; the Du vessel runs through the back, spreads over the head and extends a branch that joins the foot – Taiyang channels; the large collateral of spleen channel spreads over the chest and hypochondrium.
3. Physiological Functions
3.1 To strengthen the relations between the to interiorly – exteriorly related channels of the twelve regular channels on the body surface
The connections and relations of the two interiorly – exeriorly related channels within the region of the limbs are established and strengthened by the yin collaterals which run into the yang channels and the yang collaterals which run into the yin channels.
3.2 To command all the collaterals of the body
Divergent Collaterals are the main trunk of collaterals, and play a leading function on numerous tiny collaterals. The Luo – connecting acupoints in the branches of divergent collaterals extended from the twelve regular channels and are the converging and hub of the collateral qi. The channel qi of the collaterals becomes smaller when branching out from the major divergent collaterals. The tiny collaterals branching out from the divergent collaterals are called “ the minute cllaterals “; the collaterals distributed on the surface of the skin are called “ the superficial collaterals “. Therefore, divergent collaterals can command tiny collaterals all over the body. The collaterals of the Ren vessel distribute on the abdominal area, while the Du vessel runs on the back region. The major collateral of the spleen runs on the thoraco – hyperchondriac region; thus the collaterals strengthen the connection of the anterior, posterior and lateral aspects of the body.
3.3 To carry qi and blood to nourish the tissues of the whole body
The minute collaterals and superficial collaterals branching out from divergent collateral, from small to large, are distributed all over the body. They scatter like a network and have wide connections with tissues all over the body. Therefore, they can make the qi and blood that run in the vessel disperse from linear to facet, and give full play to their nourishing function to the whole body.
1. Basic Concept
The channel sinews are tendon and muscle systems affiliated with the twelve channels. According to the running routes of twelve regular channels, the tendons and muscles of the whole body can be divided into the three yin and three channels of the hand and foot, making up the twelve channel sinews. As the affiliated part of the channel system, the functional activities of the twelve musculatures rely on the nourishment of qi and blood from the channels and are also regulated by the twelve regular channels.
2. Distribution Regularity
The distributions of the twelve channel sinews are basically consistent with the running routes of the twelve channels on the body surface. However, the running trends are not exactly the same. Their distribution characteristics are as follows: 1.The channel sinews all run from the ends of the limbs to the head or the trunk. 2.The three yin channels sinews all the hand and foot are distributed on the inner side of the limbs, while the three yang channels sinews of hand and foot are distributed on the outer side of the limbs. 3.The channels sinews are usually distributed on the body surface, converging and gathering at the joints and skeleton. 4.Some enter into the pleuroperitoneal cavity, but do not connect to viscera.
3. Physiological Functions
3.1 Connecting the four limbs and bones, and controlling the normal movements of the joints
The channel sinews are clustered close to the joints and bones, and are able to connect and bind bones all over the body. The antagonism between the yin channel sinews and yang channel sinews harmonizes the body movements including flexion and extension, rotation and pitching. The chapter “ Discussion on Flaccidity “ in Plain Questions states, “ Zongjin (sinew connected with the genital ) controls bones and lubricates joints. “
3.2 Protecting
In addition to being attached to skeleton, channel sinews are also distributed on the superficial part of the trunk and four limbs, and have the function of protecting the human body.
1. Basic Concept
The cutaneous regions are referred to as the regions divided according to the distributions of the channels and collaterals on the surface of the body. The chapter of On Cutaneous Region in Plain Questions states, “The skin can be divided into different regions”, and “The skin is the exterior region where the channels distribute.” This chapter also states, “The cutaneous regions aremarked by the regular channels,” and “The cutaneous regions are the parts of channel system located in the superficial region of the body.” Thus, the cutaneous regions belong to the region where the channels and collaterals distribute, and the channel – qi remains.
2. Distribution Regularity
Because there are twelve regular channels, the skin of the body surface is also divided into twelve corresponding parts called the “twelve cutaneous region”. The skin areas reflected by the twelve regular channels are different from channels and collaterals. The channels have string – like distributions; the collaterals are of net – like distributions; and the cutaneous regions are the divisions on the surface. The scope of their distribution roughly pertains to the location of the running course of the channel, but it is broader than the channels and collaterals.
3. Physiological Functions
3.1 Fighting against the exogenous evils and guarding the body.
Cutaneous regions locate around the superficial areas of human body, thus they are always exposed to the exogenous evils. At the very beginning of evil invasion, the cutaneous regions, coupled with defensive qi distributed over body surface serve to deal with the situation, so the body can be well protected.
3.2 Reflecting the morphological changes of internal viscera and channels – collaterals.
Twelve cutaneous regions belong to 12 channel – collaterals respectively, which belong to viscera. Consequently, the morphological changes of viscera and channels – collaterals can manifest in the corresponding cutaneous region(s). This understanding, in clinical practice, contribute to the diagnostic for a number of diseases.
3.3 Enriching therapeutic approaches and enhancing clinical effectiveness
As for the treating approaches using needles, it is recorded in the chapter of standard neelse of Spiritual Pivot that cutaneous regions can be needled with such approaches as intermuscular needling and skin needling. The modern needling methods such as dermal and intrademal needling are all developed from these ancient appraoches.
Desides, through the stimulation and penetration, combined with application, medicinal bath, moxibustion and hot package at acupoints, the treatment aiming at cutaneous regions shows favorable effectiveness in warming qi and blood, unblocking channels – collaterals, invigorating qi mechanism and enhancing body immunity.
Channels & Collaterals Functions
Physiological Functions of the Channels and Collaterals
The channel and collateral system which takes the twelve regular channels as core has the basic functions of communicating and connecting, conveying qi and blood, reaction and conduction, as well as regulating functional balance etc.
1. Communicating and Connecting All Parts of the Body
The human body is made up of the five zang – viscera, six fu – viscera, four limbs, five sense organs, nine orifices, skin, muscles, tendons and bones. Each has its own respective physiological functions, yet performs a common organic activity of the whole. This kind of organic coordination and mutual relationship is accomplished through communication and connection by the channel system. The twelve channels, eight extraordinary channels ( vessels ) and their branches criss and cross, come in and go out, and ascend and descend. They therefore communicate the links between the viscera and the limbs and joints, the viscera and the orifices, and between the viscera and the channels. This creates an organic whole not only in organizational structure but also in physiological function, completing all kinds of complex functional activities.
2. Conveying Qi and Blood to Nourish the Whole Body
Every viscus and tissue of the human body needs nourishing and moistening by qi and blood so as to perform their normal function. Qi and blood depend upon the transportation and importation by the channels and collaterals in order to distribute and nourish the body. The channels and collaterals constantly transport qi and blood to all parts of the body to irrigate viscera and tissue internally, in addition to moistening Couti, skin, and external hair. The chapter of The Viscera as the Foundation of Human Beings in Spiritual pivot states, “ The channels and collaterals transport blood and qi to adjust the yin and yang, nourish tendons and bones, and improve joint functions.”
3. Reaction and Conduction
Reaction and Conduction mean that the channel – collatera syetem functions in response to the sensation of needling and other stimulations. It is called “ channel – collateral sensation phenomenon”. This phenomenon refers to sensations produced by the stimulation of an acupoint. These sensation may include soreness, numbness, expansion, and heaviness, and can be transmitted and spread along the running course of channels and collaterals. This phenomenon is called “ getting qi “ or “ arrival of qi “.
4. Regulating Functional Balance for the body
The channels and collaterals circulate qi and blood and coordinate yin and yang in order to keep a relative balance of bodily activities. When a disease occurs in the body, the symptoms related to the disharmony of qi and blood, and excess or deficiency of yin and yang emerge. These can be treated by acupuncture and moxibustion therapy to stimulate the channel’s regulative function, and achieve the purpose of “ reducing the excess and reinforce the deficiency to making yin and yang balanced.” (Chapter of Discussion on the five sections on needling and comments on the genuine qi and pathogenic factors in spiritual pivot )
Channels & Collaterals Applications
Application of the Channel – Collateral Theory
As an important constituent part of TCM basic theories, channel-collateral theory can not only be used to explain physiological functions, but also to expound pathological changes, and guide the diagnosis and treatment of diseases.
1. Expounding Pathological Changes
Because channels and collaterals have functions of communicating the exterior and interior, connecting viscera, conveying qi and blood, and reacting and conducting, so in pathological conditions, channels and collaterals may become the pathways of transmitting evils and reflecting pathological changes, therefore, the theory of channels and collaterals can be used to explain the pathological changes in the human body. It is stated in the chapter of Discussion on Skin Divisions in Plain Ouestions, “ Retention of evil in the skin makes the couli ( muscular interstice ) open, giving rise to the invasion of evil into collaterals. When the collaterals are full, it will flow into the channels. When the channels are full, it will get into the zang – fu viscera.” It explains that channels and collaterals are the pathways that exogenous evil is transmitted into zang – fu viscera via the skin and couli ( muscular interstice ). Meanwhile, the channels and collaterals can be pathways that pathological changes among viscera influce each other. For example, Foot Jueyin Liver Channel runs stomach, and connects with the Lung Channel. Therefore, the stagnation of liver – qi can offend stomach, and excessive anger can offend lung and so on. Channels and collaterals can also reflect visceral visceral pathological changes on certain parts of the body surface or its corresponding orifices. For example, liver qi stagnation is always manifested as the pain in hypochondrium or lower abdomen; excess of stomach fire is always manifested as swollen gums; and inflammation of liver fire is always manifested as red eyes and so on.
2. Guiding the Diagnosis of Diseases
Because the channels and collaterals have fixed courses of extension in the body and a fixed connection with the viscera, the symptoms and signs of visceral disease are easily manifested. In clinical practice, the channel – collateral system can be the foundation of diagnosis. For example, pain in both hypochondriac regions is mainly due to liver and gallbladder disease; while pain in the forehead is related to the Yangming Channel. Pain on both lateral sides is associated with the Shaoyang Channel, and pain in the occipital region and nape relates with the Taiyang Channel. Pain in the vertex relates with the Jueyin Channel. The chapter of Qualifications of Acupuncturists in Spiritual Pivot points out, “ When diagnosing a disease, the doctor should find out where the disease locates, distinguish cold syndromes from cold ones and make sure which channel(s) is/are affiliated. “which points out the significance of the channels and collaterals in clinical treatment.
3. Guiding Clinical Treatment
The channel – collateral theory is widely used to guide the clinical treatment of disease in various departments, especially being the theoretical basis for acupuncture, moxibustion, Tuina and pharmacotherapy.
The treatment of disease with acupuncture and moxibustion is attained through puncturing the acupoint or burning moxa over the acupoint to smooth channel qi. These modalities restore the channel’s function of regulating viscera qi and blood of the body in order to achieve the purpose of curing disease. Pharmacotherapy also utilizes the channels. A medicine utilizes the conduction and transportation of the channel – collateral system to target a diseased area, enact a therapeutic effect, and sure disease.
Through long and repeated practice, medical scholars found that Chinese medicinals have selective therapeutic effect on the illness related to a certain channel – collateral and its affiliated viscus. Based on this, they founded the theory of “ channel tropism of medicinal ”, and “ guiding action.” For example, in a formula for treatment of headache, modification may be made according to the channel distribution regions. Qianghuo ( Rhizoma Notopteryii ) is used for headache in the Taiyang channel region; Baizhi ( Radix Angelicae ) for headache in the Ynagming channel region ; Chaihu ( Radix Bupleuri ) for headache in the Shaoyang channel region. These three herbs not only pertain to the Taiyang, Yangming, and Shaoyang channels of the hand and foot, but also guide other herbs through the above channels in order to achieve a stronger therapeutic effect.