阴跷者，足少阴之别脉，其脉起于跟中，足少阴然谷穴之后，（然谷在内踝前下一寸陷中）同足少阴循内踝下
照海穴，（在内踝下五分）上内踝之上二寸，以交信为 。（交信在内踝骨上，少阴前太阴后筋骨间）直上循阴
股入阴，上循胸里入缺盆，上出人迎之前，至咽咙，交贯冲脉，入 内廉，上行属目内 ，与手足太阳、足阳明、阳
跷，五脉，会于睛明而上行。（睛明在目内 外一分宛宛中）凡八穴。
张紫阳八脉经云∶八脉者∶冲脉在风府穴下，督脉在脐后，任脉在脐前，带脉在腰，阴跷脉在尾闾前
阴囊下，阳跷脉在尾闾后二节，阴维脉在顶前一寸三分，阳维脉在顶后一寸三分。凡人有此八脉，俱属阴
神，闭而不开，惟神仙以阳气冲开，故能得道。八脉者，先天大道之根，一气之祖。采之惟在阴跷为先，
此脉才动，诸脉皆通。次督、任、冲三脉，总为经脉造化之源。而阴跷一脉，散在丹经，其名颇多∶曰天
根、曰死户、曰复命关、曰酆都鬼户、曰死生根，有神主之，名曰桃康，上通泥丸，下透涌泉。倘能知
此，使真气聚散，皆从此关窍，则天门常开，地户永闭，尻脉周流于一身，贯通上下，和气自然上朝，阳
长阴消，水中火发，雪里花开。所谓天根月窟闲来往，三十六宫都是春。得之者，身体轻健，容衰返
壮，昏昏默默，如醉如痴，此其验也。要知西南之乡乃坤地，尾闾之前，膀胱之后，小肠之下，灵龟之
上，此乃天地逐日所生，气根产铅之地也，医家不知有此。
濒湖曰∶丹书论及阳精河车。皆往往以任、冲、督脉、命门、三焦为说，未有专指阴跷者。而紫阳八脉
经所载经脉，稍与医家之说不同。然内景隧道，惟返观者能照察之，其言必不谬也。
阴跷脉，是足少阴肾经的别行分支。其脉起始于足跟中部，位于足少阴肾经然谷穴之后（然谷穴位于内踝前下方一寸处的凹陷中），与足少阴肾经并行，经过内踝下方的照海穴（位于内踝下五分处），上行至内踝上方二寸处，经过交信穴（交信穴位于内踝骨上方，在足少阴肾经之前、足太阴脾经之后的筋骨之间）。随后直上沿大腿内侧进入阴部，向上沿胸部内部进入缺盆，上行至人迎穴之前，到达咽喉，与冲脉交会贯通，进入大腿内侧，上行归属于目内眦，与手太阳小肠经、足太阳膀胱经、足阳明胃经、阳跷脉这五条经脉，在睛明穴交会后继续上行。（睛明穴位于目内眦外一分处的凹陷中）共有八个穴位。
张紫阳在《八脉经》中说：八脉之中，冲脉位于风府穴下方，督脉位于脐后，任脉位于脐前，带脉环绕腰部，阴跷脉位于尾闾前、阴囊下方，阳跷脉位于尾闾后两节处，阴维脉位于头顶前一寸三分处，阳维脉位于头顶后一寸三分处。普通人拥有这八条奇经，但都属于“阴神”范畴，处于闭合状态而不通畅，只有神仙以阳气冲开它们，因此能够得道。八脉是先天大道的根本，是一气的祖源。修炼采气以阴跷脉为先导，这条脉一旦发动，其他各脉皆通。其次是督脉、任脉、冲脉这三条脉，总称为经脉造化的源头。而阴跷一脉，散见于各种丹经之中，名称很多：叫做天根、死户、复命关、酆都鬼户、死生根，有神灵主管它，名叫桃康，上通泥丸宫，下透涌泉穴。如果能够知晓此理，使真气聚散都通过这个关窍，那么天门常开，地户永闭，尻脉在周身周流，贯通上下，和气自然上朝，阳气增长阴气消退，水中火发，雪里花开。这就是所谓的“天根月窟闲来往，三十六宫都是春”。得到这种境界的人，身体轻健，容貌衰老返归年轻，精神昏昏默默，如醉如痴，这就是验证。要知道西南方向属于坤地，即尾闾之前，膀胱之后，小肠之下，灵龟之上，这是天地每日所生之气，产铅之地，医家不知道这一点。
濒湖（李时珍自称）说：丹书论述及阳精河车时，往往以任脉、冲脉、督脉、命门、三焦来解说，没有专门指向阴跷脉的。而张紫阳《八脉经》所载的经脉，稍微与医家的说法不同。然而内在的经络隧道，只有返观内视的人才能察看清，他的话必定不会谬误。
Yin Qiao Mai (Yin Heel Vessel) is a divergent branch of the Foot-Shaoyin Kidney Meridian. Its vessel originates from the middle of the heel, behind the Ran Gu point (Rangu, KI2) of the Foot-Shaoyin Kidney Meridian (Rangu is located in the depression one cun anterior and inferior to the medial malleolus). It travels with the Foot-Shaoyin Kidney Meridian along the lower aspect of the medial malleolus through the Zhaohai point (Zhaohai, KI6) (located five fen below the medial malleolus), ascends two cun above the medial malleolus, passing through the Jiaoxin point (Jiaoxin, KI8) (located above the medial malleolus bone, between the tendons and bones, anterior to the Foot-Shaoyin and posterior to the Foot-Taiyin). It then goes straight up along the medial aspect of the thigh into the genital region, ascends along the interior of the chest entering the Clavicular fossa (Quepen), ascends anterior to the Yingchang point (Yingchang, ST9), reaches the throat, intersects and penetrates the Chong Mai (Chong Vessel), enters the medial aspect of the thigh, ascends and attaches to the inner canthus of the eye. At the Jingming point (Jingming, BL1) (located in the depression one fen lateral to the inner canthus), it meets with the Hand-Taiyang Small Intestine Meridian, Foot-Taiyang Bladder Meridian, Foot-Yangming Stomach Meridian, and Yang Qiao Mai (Yang Heel Vessel)—five vessels in total—and ascends after intersection. There are eight acupoints in total.
Zhang Ziyang states in the *Classic of the Eight Vessels*: Among the Eight Vessels, the Chong Mai is below the Fengfu point (Fengfu, GV16); the Du Mai (Du Vessel) is posterior to the umbilicus; the Ren Mai (Ren Vessel) is anterior to the umbilicus; the Dai Mai (Dai Vessel) encircles the waist; the Yin Qiao Mai is anterior to the Weilü area and inferior to the scrotum; the Yang Qiao Mai is two segments posterior to the Weilü area; the Yin Wei Mai (Yin Linking Vessel) is one cun three fen anterior to the vertex; and the Yang Wei Mai is one cun three fen posterior to the vertex. Ordinary humans possess these eight vessels, but they belong to the "Yin Spirit" and remain closed and unpatent. Only immortals can open them with Yang Qi, thereby attaining the Dao. The Eight Vessels are the root of the primordial Great Dao and the ancestor of the One Qi. In gathering Qi, priority is given to the Yin Qiao Mai. Once this vessel moves, all other vessels become patent. Subsequently, the Du, Ren, and Chong vessels serve as the source of creation for the meridians. The Yin Qiao Mai appears scattered in various alchemical classics under many names: Tian Gen (Heavenly Root), Si Hu (Gate of Death), Fu Ming Guan (Return-to-Life Pass), Feng Du Gui Hu (Ghost Gate of Fengdu), and Si Sheng Gen (Root of Dead Birth). A deity governs it, named Tao Kang. It connects upward to the Niwan Palace and downward through the Yongquan point (Yongquan, KI1). If one understands this and allows the True Qi to gather and disperse through this passageway, the Heavenly Gate remains open, the Earthly Gate remains closed, the Kao Mai circulates throughout the body, penetrating upper and lower levels, and Harmonious Qi naturally ascends. Yang grows while Yin diminishes; Fire arises from Water, and flowers bloom in snow. This is described as "Freely visiting the Heavenly Root and Lunar Cavern, making all thirty-six palaces spring-like." Those who attain this experience lightness and vigor in their bodies, reversing aging and restoring youth. Their minds are tranquil and obscure, like being drunk or in a trance; this is the verification. One must know that the Southwest direction corresponds to Kun Earth, specifically the area anterior to the Weilü, posterior to the bladder, inferior to the small intestine, and superior to Linggui. This is where the Qi generated daily by Heaven and Earth resides, the place of producing Lead. Physicians are unaware of this.
Binhu (Li Shizhen's pseudonym) says: Alchemical texts discussing Yang Essence and the River Cart often refer to the Ren, Chong, and Du vessels, Mingmen (Gate of Life), and Sanjiao (Triple Burner), but rarely specifically designate the Yin Qiao Mai. The meridians described in Zhang Ziyang's *Classic of the Eight Vessels* differ slightly from medical theories. However, the internal pathways of the collaterals can only be observed clearly through introspective vision (Fan Guan Nei Shi); thus, his words must not be erroneous.