灵枢经·卫气 Defensive Qi
黄帝曰：五藏者，所以藏精神魂魄者也；六府者，所以受水谷而行化物者也。其气内干五藏，而外络肢节。其浮气之不循经者，为卫气；其精气之行于经者，为营气。阴阳相随，外内相贯，如环之无端。亭亭淳淳乎，孰能窃之。然其分别阴阳，皆有标本虚实所离之处。能别阴阳十二经者，知病之所生；候虚实之所在者，能得病之高下；知六府之气街者，能知解结契绍于门户；能知虚石之坚软者，知补写之所在；能知六经标本者，可以无惑于天下。
歧伯曰：博哉！圣帝之论。臣请尽意悉言之。足太阳之本，在限以上五寸中，标在两络命门。命门者，目也。足少阳之本，在窍阴之间，标在窗笼之前。窗笼者，耳也。足少阴之本，在内踝下上三寸中，标在背输与舌下两脉也。足厥阴之本，在行间上五寸所，标在背腧也。足阳明之本，在厉兑，标在人迎，颊挟颃颡也。足太阴之本，在中封前上四寸之中，标在背腧与舌本也。
手太阳之本，在外踝之后，标在命门之上一寸也。手少阳之本，在小指次指之间上二寸，标在耳后上角下外眦也。手阳明之本，在肘骨中，上至别阳，标在颜下合钳上也。手太阴之本，在寸口之中，标在腋内动也。手少阴之本，在锐骨之端，标在背腧也。手心主之本，在掌后两筋之间二寸中，标在腋下下三寸也。
凡候此者，下虚则厥，下盛则热；上虚则眩，上盛则热痛。故石者，绝而止之，虚者，引而起之。
请言气街，胸气有街，腹气有街，头气有街，胫气有街。故气在头者，止之于脑；气在胸者，止之膺与背腧；气在腹者，止之背腧，与冲脉于脐左右之动脉者；气在胫者，止之于气街，与承山踝上以下。取此者，用毫针，必先按而在久应于手，乃刺而予之。所治者，头痛眩仆，腹痛中满暴胀，及有新积。痛可移者，易已也；积不痛，难已也。
Huangdi said: 'The five viscera are that which store the essence, spirit, ethereal soul (hun), and corporeal soul (po); the six bowels are that which receive water and grain and carry out the transformation of substances. Their qi penetrates within to the five viscera, and connects without to the limbs and joints. The floating qi that does not follow the channels is defensive qi; the essential qi that travels through the channels is nutritive qi. Yin and yang follow one another, exterior and interior interlink, like a ring without end — so tranquil and so pure and undivided that who could ever steal it away? Yet in distinguishing yin and yang, each channel has its branch and root, and its places of separation between deficiency and excess. One who can distinguish the twelve channels of yin and yang can know whence disease arises. One who observes where deficiency and excess reside can determine whether the disease is located above or below. One who knows the qi-thoroughfares of the six bowels can know how to resolve knots and bind together the gateways of the body. One who knows whether a deficient or a replete condition is soft or hard can know where to supplement and where to drain. One who knows the branches and roots of the six channels can be free of confusion throughout the world.'
Qibo said: 'How broad is the sage sovereign's discourse! Allow your servant to express his understanding fully. The root of the Foot Taiyang channel lies within five cun above the heel; its branch lies at the two linking vessels of the Gate of Life. The Gate of Life is the eyes. The root of the Foot Shaoyang channel lies between Qiaoyin; its branch lies in front of the Window Cage. The Window Cage is the ear. The root of the Foot Shaoyin channel lies within three cun above the inner ankle; its branch lies at the back transport points and the two vessels beneath the tongue. The root of the Foot Jueyin channel lies about five cun above Xingjian; its branch lies at the back transport points. The root of the Foot Yangming channel lies at Lidui; its branch lies at Renying, at the cheeks flanking the pharynx. The root of the Foot Taiyin channel lies within four cun above and in front of Zhongfeng; its branch lies at the back transport points and the root of the tongue.'
The root of the Hand Taiyang channel lies behind the outer wrist bone; its branch lies one cun above the Gate of Life. The root of the Hand Shaoyang channel lies two cun above the point between the fourth and little fingers; its branch lies behind the ear, below the upper corner and the outer canthus. The root of the Hand Yangming channel lies within the elbow bone, extending up to Biyang; its branch lies below the forehead where it meets above the cheekbone. The root of the Hand Taiyin channel lies at the Inch Opening; its branch lies at the pulsating vessel within the armpit. The root of the Hand Shaoyin channel lies at the tip of the styloid bone at the wrist; its branch lies at the back transport points. The root of the Hand Jueyin, the Pericardium channel, lies two cun above the wrist, between the two sinews; its branch lies three cun below the armpit.
In examining these, when the lower root is deficient, reversal-cold occurs; when the lower is exuberant, heat occurs. When the upper branch is deficient, dizziness occurs; when the upper is exuberant, heat and pain occur. Thus, where there is hardness and stagnation, one should cut it off and halt it; where there is deficiency, one should draw the qi up and raise it.
Allow me to speak of the qi-thoroughfares: the chest has its qi-thoroughfare, the abdomen has its qi-thoroughfare, the head has its qi-thoroughfare, and the shin has its qi-thoroughfare. Thus, when qi is located in the head, one halts it at the brain; when qi is located in the chest, one halts it at the chest and the back transport points; when qi is located in the abdomen, one halts it at the back transport points and at the pulsating vessels of the Penetrating Vessel to the left and right of the navel; when qi is located in the shin, one halts it at Qijie, the qi-thoroughfare point, and at Chengshan and the points above the ankle. To needle these points, one uses the fine filiform needle; one must first press upon the point for a long while until a response is felt beneath the hand, and only then does one needle and administer treatment. What may be treated in this way includes headache, dizziness and collapse, abdominal pain with fullness and sudden distension, and newly formed accumulations. When the pain shifts from place to place, the condition is easy to cure; when there is an accumulation without pain, it is difficult to cure.