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 经络系统的组成
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.
Tab. 2 The Nomenclature and Classification of the Twelve Meridians 表2.十二正经的命名和归类
Tab.2 shows that every meridian consists of three parts. 表2说明了每条经都由三部分组成。
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.(To Be Continued)