属足少阴肾经（《灵枢》曰∶阴中之太阴，肾也，其原出于太溪。太溪，内踝之后，跟
骨之上，陷者中也。为输。《素问》曰∶下部地，足少阴也，以候肾。注∶肾脉在足内踝后，跟骨上陷中，太
溪之分，动应于手。又曰∶阴气不用，饥不欲食，咳唾则有血数点，病本于肾。太溪绝，死不治。吴鹤皋曰∶
太溪者，肾脉也，真元之气聚于斯。若此脉不衰，则元气犹存，病虽危，尚可治也。沈承之曰∶内踝骨下，略
近后跟缘上，动脉陷者中，名太溪穴。此穴有脉则生，无脉则死。盖肾者生气之源，十二经之本，太溪则其输
穴也。其脉动而不息者，真气充达于一身也。若真气惫，肾气绝，则其脉不动而死矣。纵冲阳有脉，尤能进食，
亦主死也）。
属足少阴肾经（《灵枢》曰∶足少阴之脉，起于小趾之下，斜走足心。所生病者，足下
热而痛。又曰∶肾出于涌泉，涌泉者足心也，为井木。又曰∶足少阴之筋，其病足下转筋。《素问》曰∶阴脉
者集于足下，而聚于足心，故阳气胜，则足下热也。沈承之曰∶足三阴之脉，集于足下，足少阴之经，聚于足
心，阳胜则阴虚，故足下热。丹溪曰∶热从足下起入腹者，虚之极也，正所谓阴虚也）。
（足跟也）属足少阴肾经（《灵枢》曰∶足少阴之筋，斜走内踝之下，结于踵，与太阳之
筋合。又曰∶足少阴之别，名曰大钟，当踝后绕跟，别走太阳。《素问》曰∶肾痹者善胀，尻以代踵，脊以代
头。注∶肾者，
胃之关也。关不利，则胃气不转，故善胀。尻以代踵，谓足挛急也；脊以代头，谓身 曲也。肾气不足而受邪，
故不能伸展也。）又属足太阳膀胱经。（《灵枢》曰∶足太阳之筋，循足外侧结于踵，又曰∶足太阳之下，血
气盛，则跟肉满，踵坚，气少血多，则瘦，跟空，血气皆少，则善转筋，踵下痛）。
Taixi (KI3) belongs to the Foot-Shaoyin Kidney Meridian. The *Ling Shu* states: "The Yin among Taiyin is the Kidney, and its Yuan-Source Qi issues from Taixi." Taixi is located posterior to the medial malleolus, above the calcaneus, in the depression. It is the Shu-Stream point. The *Su Wen* states: "The lower region of the earth corresponds to the Foot-Shaoyin, used to observe the state of the Kidney." The commentary notes: The Kidney pulse is located posterior to the medial malleolus of the foot, in the depression above the calcaneus, at the distribution of Taixi, where the movement can be felt by hand. It further states: "If Yin Qi fails to function, there will be hunger without desire to eat, and coughing with spitting of blood droplets; the disease originates in the Kidney. If Taixi ceases, death ensues and cannot be treated." Wu Hegao said: "Taixi is the site of the Kidney pulse, where the True Primal Qi gathers. If this pulse does not decline, then the Primal Qi still exists; even if the illness is critical, it may still be treatable." Shen Chengzhi said: "Below the medial malleolus bone, slightly closer to the upper edge of the posterior heel, in the depression where the artery beats, is named the Taixi acupoint. If there is a pulse at this point, life prevails; if there is no pulse, death occurs. This is because the Kidney is the source of vital Qi and the root of the twelve meridians, while Taixi is its Shu-Stream point. The continuous beating of its pulse indicates that True Qi is abundant and reaches the whole body. If True Qi becomes exhausted and Kidney Qi is severed, the pulse stops beating and death follows. Even if the Chongyang pulse is present and the patient can still eat, death is still indicated."
Zuxin (Foot Center) belongs to the Foot-Shaoyin Kidney Meridian. The *Ling Shu* states: "The meridian of Foot-Shaoyin originates below the little toe and runs obliquely to the center of the foot." Diseases generated by this meridian include heat and pain under the sole. It further states: "The Qi of the Kidney issues from Yongquan (KI1), which is the center of the foot, and is the Jing-Wood point." It also states: "Diseases of the sinews of Foot-Shaoyin manifest as spasms (cramps) under the foot." The *Su Wen* states: "Yin meridians gather at the soles of the feet and converge at the foot center; therefore, when Yang Qi prevails, heat occurs under the foot." Shen Chengzhi said: "The three Yin meridians of the foot gather at the soles, and the meridian of Foot-Shaoyin converges at the foot center. When Yang prevails, Yin becomes deficient, hence heat under the foot." Danxi said: "Heat rising from the soles into the abdomen indicates extreme deficiency, which is precisely what is meant by Yin deficiency."
Zhong (Heel) belongs to the Foot-Shaoyin Kidney Meridian. The *Ling Shu* states: "The sinews of Foot-Shaoyin run obliquely below the medial malleolus and knot at the heel, combining with the sinews of the Taiyang." It further states: "The Luo-Connecting vessel of Foot-Shaoyin is named Dazhong (KI4); it is located behind the ankle, winds around the heel, and branches off to the Taiyang." The *Su Wen* states: "Patients with Kidney Bi tend to have distension; they use their buttocks instead of their heels to walk, and their spine instead of their head to stand upright." The commentary notes: The Kidney is the gate of the Stomach. If the gate is obstructed, Stomach Qi cannot rotate, leading to frequent distension. "Using the buttock instead of the heel" refers to leg contractures; "using the spine instead of the head" refers to spinal curvature. Due to insufficient Kidney Qi and invasion of pathogenic factors, extension is impossible. Zhong also belongs to the Foot-Taiyang Bladder Meridian. The *Ling Shu* states: "The sinews of Foot-Taiyang follow the lateral side of the foot and knot at the heel." It further states: "In the lower part of Foot-Taiyang, when Blood and Qi are abundant, the heel flesh is full and the heel is firm; when Qi is scarce and Blood is abundant, the heel is thin and hollow; when both Blood and Qi are scarce, spasms easily occur, and there is pain below the heel."