MERIDIANS AND COLLATERALS-THE PATHWAYS TO LINK THE WHOLE BODY

The meridian-collateral theory is concerned with the physiological functions and the pathological changes of the meridian-collateral system, and their relationships with zang-fu organs. It is an important component of the theoretical system of TCM. And it is considered as a theoretical basis of all clinical subjects of TCM, especially that of acupuncture, moxibustion, tuina and qigong. Besides, it guides the clinical practice of other branches of TCM.

The meridians and collaterals are pathways along which qi and blood circulate through the whole body. The meridians are the major trunks of the meridian-collateral system and run longitudinally within the body, while the collaterals are the branches of the meridians and are reticularly distributed over the whole body. Hence, the meridians and collaterals, connecting the zang-fu organs with extremities, the upper with the lower and the internal with ihe external portions of the body, make all the body's organs and tissues an organic whole.

The Composition of the Meridian-Collateral System

The meridian-collateral system consists of meridians and collaterals as well as their subsidiary parts. This system, internally, links the zang-fu organs and, externally, joins the tendons, museles and skin.

The meridians are classified into three categories: the regular meridians and the extra meridians and the divergent meridians. There are twelve regular meridians, namely the three yin meridians as well as the three yang meridians of the hands and feet. They are known collectively as "the twelve regular meridians", which are the main passages for qi and blood circulation and start and terminate at given seats, run along fixed routes and meet indefinite orders. They are directly connected with the relevant zang-fu organs. The eight extra meridians are composed of Du,Ren, Chong, Dai, Yinqiao, Yangqiao, Yinwei and Yangwei meridians. They are interlated with the twelve regular meridians and perform the functions of dominating, connecting and adjusting the twelve regular meridians. And they are not directly related to the internal organs in addition, the twelve divergent meridians are the extensions of the twelve meridians. They originate from the limbs, run deeper into the zang-fu organs and emerge from the shallow neck.

Their action is to enhance the Links between every pair of meridians exteriorly-interiorly related in the twelve meridians and complement the organs and bodily areas to which the regular meridians can not get.

The collaterals are the branches of the meridians. They are divided into three groups: the divergent collaterals, superficial collaterals and tertiary collaterals. The divergent collaterals are the larger and main collaterals. The divergent collaterals originate from the twelve meridians as well as Du and Ren meridians respectively. Together with a large splenic collateral, they are altogether "fifteen divergent collaterals". Their chief task is to strengthen the links between every pair of meridians exteriorly-interiorly related on the body surface. The superficial collaterals are ones that run through the surface layer of the human body, and often emerge on the surface. And the tertiary collaterals refer to the smallest and the thinnest ones of the whole body.

In addition, there are the subsidiary parts of the meridian system, including the twelve skin zones and twelve musculature zones. Therefore, they are the parts that connect the twelve meridians with the superficial portions and the muscular portions of the body respectively. Considering the important place of the twelve meridians and the eight extra meridians in the meridian-collateral system. we are going to take them as the main subject for discussion.

1 ) Hand or foot:

The meridians starting or terminating at the hand are named "Hand", while those starting or terminating at the foot are named "Foot". So the twelve meridians are divided into four groups: three yin meridians of hand, three yang meridians of hand, three yin meridians of foot, and three yang-meridians of foot. Each of the meridian is named according to the medial or the lateral aspect of hand or foot, the names to which zang and fu pertain, and the nature of yin or yang.

2 ) Yin or yang:

The meridians going in the medial aspect of the limbs are named "yin", whereas those in the lateral aspects are named "yang". The medial aspect of the limbs is subdivided into the anterior border, midline and the posterior border. And the yin meridians running through these parts are named Taiyin,Jueyin and Shaoyin respectively. The lateral surface of the limbs is also subdivided into the anterior border, the midline and the posterior border. And yang meridians are termed "Yangming","Shaoyang", and "Taiyang".

3) Zang or fu:

The nomenclature of zang or fu is determined in the light of the nature to which zang or fu pertains. For example, the meridian pertaining to the kidney is named the kidney meridian, and the rest may be deduced by analogy.

To sum up, it is quite evident that there is no name that does not involve hand or foot, yin or yang, zang-organ or fu-organ in the twelve meridian.

Courses, Connections, Distributions, Exterior-lnterior Relations and Flowing Order of the Twelve Meridians

1. The Coursing and Connecting Law of the Twelve Meridians

The coursing and connecting law of the twelve meridians is: the three yin meridians of the hand travel from the chest to the end of the fingers where they connect with the three yang meridians of the hand; the three yang meridians of the hand go up from the end of the fingers to the head on which they connect with the three yang meridians of the foot; the three yang meridians of the foot descend from the head to the the end of toes where they join the three yin meridians of the foot; the three yin meridians of the foot ascend from the toes to the abdomen and chest in which they meet the three yin meridians of the hand. Thus, the twelve meridians are connected with each other, forming a circle like pathway along which yin and yang smoothly circulate without terminus.

2. Distributions and Exterior-Interior Relations of the Twelve Regular Meridians1) Distributions

The twelve meridians are distributed symmetrically on the left and right sides of the body and run along their fixed courses. Distribution in the limbs: The medial aspect of the limbs attributes to yin, the lateral to yang. Each limb is distributed by Taiyin and Yangming meridians are on the anterior border, Shaoyin and Taiyang meridians are on the posterior border, and Jueyin and Shaoyang meridians are on the midline.

Distribution on the head and face: Yangming meridians run through the face and forehead, Taiyang meridians run through the cheek, vertex and occiput of the head and Shaoyang meridians run through both sides of the head.

Distribution in the body trunk: The three yang meridians of hand run through the scapular part. Among the three yang meridians of foot, Yangming meridians run in the front of the trunk (thoracico-abdominal aspect), Taiyang meridians along the back (the dorsal aspect) , and Shaoyang meridians along the sides. All the three yin meridians of the hand come out of the axillae without exception, all the three yin meridians of foot run along the ventral aspect. The meridians running through the ventral aspect from the medial to the lateral are, in turn, termed Foot-Shaoyin, Foot-yangming, Foot-Taiyin and Foot-Jueyin(note: as regards the medial sides of the two lower limbs, at 8cun (24cm) above the medial malleoli, Jueyin is located in theanterior, Taiyin in the middle and Shaoyin in the posterior part.)

The Exterion-Interior Relations between the Twelve Meridians

The twelve regular meridians, connected with each other by the divergent meridians and divergent collaterals, form six pairs of exterior-interior relationships. Their exterior-interior relationships are as follows: the Large Intestine Meridian of Hand-yangming and the Lung Meridian of Hand-Taiyin; the Tri-energizer Meridian of Hand-Shaoyang and the Pericardium Meridian of Hand-Jueyin; the Small intestine Meridian of Hand-Taiyang and the Heart Meridian of Hand-Shaoyin; the Stomach Meridian of Foot-yangming and the spleen Meridian of Foot-Taiyin; the Gallbladder Meridian of foot-Shaoyang and the Liver Meridian of Foot-Jueyin; and the Urinary Bladder Meridian of Foot-Taiyang and the Kidney meridian of Foot-Shaoyin. The Taiyang meridianand Shaoyin meridian of foot are exteriorly-interiorly related, and so are the Shaoyang meridian and the Jueyin meridian of foot,and the Yangming meridian and Taiyin meridian of foot. These are called the"yin and yang of foot"; while the Taiyang meridian and the Shaoyin meridian of hand are exteriorly-interiorly related, and so are the Shaoyang and the Jueyin meridians, and the Yangming and the Taiyin meridians of hand. These are called the"yin and yang of hand".

The exterior-interior relationship of the twelve meridians not only strengthen the connection between each specific pair of meridians with exterion-interior relationship, but also promote each pair of zang-fu with the exterior-interior relationship to coordinate each other physiologically and influence each other pathologically. In treatment, acupoints of the two meridians with the exterior-interior relationship may be alternatively used.

3) The Flowing Order of the Twelve Meridians

The circulation of qi and blood inside the Twelve meridians is like the circular movement endlessly. Their circulation starts from the lung meridian of Hand-Taiyin, runs to the liver meridian.


经络－人体联络的通道

经络理论是有关经络系统的生理功能和病理变化以及和脏腑之间关系的理论。它是中医理论系统的重要组成部分，被认为是所有中医临床学科特别是针灸、推拿和气功的理论基础。另外，它还指导其它分支学科的临床实践。

经络是气血循行全身的通道。经是经络系统的主干，纵行于人体，而络是经的分支，呈网状分布于全身。因此，经络沟通人体脏腑肢节，上下内外，使人体的脏腑组织成为一个有机整体。

经络系统的组成

经络系统由经和络互补而成。这个系统在内联络脏腑组织，在外沟通筋骨肌肤。

经可以分为三类：正经、奇经和经别。有十二正经即手足三阴三阳经。它们被总称为“十二正经”，是气血循行的主要通道，有固定的起止点，按照一定的路径循行并按一定顺序交接。它们与相对应的脏腑直接相连。奇经八脉由督、任、冲、带、阴蹻、阳蹻、阴维和阳维脉组成 。它们与十二正经相互联系，并行使控制、联系和调节十二正经的功能。另外，它们不与脏腑直接相关。十二经别是十二正经的延续。它们起于四肢，深入脏腑，浅出于项部。它们的作用是加强十二正经表里两经的联系，并补充十二正经所不能到达的脏腑和身体区域。

络是经的分支，可分为三类：别络、浮络和孙络。起源于十二正经和任督二脉的别络和脾之大络统称为“十五别络”。它们的作用是加强表里两经在体表上的联系。浮络循行于人体的表层并常出于体表。孙络是整个人体中最细小的络脉。

此外，尚有经络系统的附属部分包括十二皮部和十二经筋。因此，它们是分别连接人体浅表和肌肉的部分。考虑到十二正经和奇经八脉是经络系统的重要组成部分，我们将以其为主题进行讨论。

(1)手或足

经脉起于或止于手者命名为“手”，起于或止于足者命名为“足”。所以，十二正经可分为四组：手三阴经，手三阳经，足三阴经，足三阳经。每条经都是根据其所在手足的内外面的位置、脏腑归属和阴阳性质命名的。

(2)阴或阳

循行于四肢内侧的经脉命名为“阴”，而循行于外侧者为“阳”。四肢内侧又可分为前、中、后三部，阴经循行于该部分的分别称为太阴、厥阴和少阴。四肢外侧同样可以分为前、中、后三部。阳经循于此者分别为阳明、少阳和太阳。

(3)脏或腑

脏或腑的命名是根据脏或腑的归属决定的。例如，属于肾的经脉命名为肾经，其余由此类推。

总之，很显然十二正经中没有不以手足、阴阳、脏腑命名的。

十二正经的起源、交接、分布、表里关系和走行规律

1.十二正经的起源和交接规律

十二正经的起源和交接规律是：手三阴经起于胸部行至手指端，在此与手三阳经交接；手三阳经由手指端上行至头，在此与足三阳经相交接；足三阳经由头向下行至脚趾头处，在此与足三阴经相交接；足三阴经由脚趾头处上行至胸腹部，在此与手三阴经相交接。这样，十二正经彼此联系，形成了一个阴阳畅通循行的通道，如环无端。

2.十二正经的分布和表里关系

十二正经对称的分布于人体的左右两边，并按一定的路径循行。在四肢的分布是：阴经分布于四肢的内侧面，阳经分布于四肢的外侧面。太阴和阳明分布于肢体的前部，少阴和太阳分布于后部，厥阴和少阳分布于中部。

头面的分布：阳明经行于面额部，太阳经行于颊部、头顶及枕部，少阳行于头的两侧。

在躯干部的分布：手三阳经行于肩胛部。足三阳经当中，阳明经行于前腹部，太阳经沿背部循行，少阳行于两侧。所有的手三阴经无一例外的起于腋窝部，所有的足三阳经沿腹部循行。沿腹部循行的经脉由内至外的顺序是：足少阴经、足阳明经、足太阴经和足厥阴经。(注释：在双下肢，踝上8寸(24厘米)以下为厥阴在前，太阴在中，少阴在后。)

十二正经的表里关系

十二正经通过经别和别络彼此联系，形成了六对表里关系。它们的表里关系如下：手阳明大肠经和手太阴肺经；手少阳三焦经和手厥阴心包经；手太阳小肠经和手少阴心经；足阳明胃经和足太阴脾经；足少阳胆经和足厥阴肝经；足太阳膀胱经和足少阴肾经。足太阳和足少阴经相表里，足少阳和足厥阴经相表里，足阳明经和足太阴经相表里。这些称为“足阴阳经”。而手太阳经和手少阴经相表里，手少阳和手厥阴经相表里，手阳明经和手太阴经相表里。这些称为“手阴阳经”。

十二正经的表里关系不仅加强了表里两经的联系，而且加强了每对相表里脏腑之间的联系使它们在生理上相互协调，在病理上相互影响。在治疗上，表里两经的穴位可以相辅为用。

3. 十二正经的走行规律

十二正经中气血的循行如环无端。它们起于肺经通往肝经。