水为阴，火为阳。水火之中，火尤重焉。盖水者阴
也，阴不能生人，必藉火之阳而后能生。故水必藉火而后可饮，谷必藉火而后可食。夫在地为水，在天为寒，
在地为火，在天为热，阳热之气，能生万物，若遇阴寒，物必杀矣。医者于水火之中，而知重轻之理，则
生者多而杀者少也。
经云∶阴阳者，有名而无形。数之可十，推之可百；数之可千，推之可万；万之大，不可胜数。试以大
体言之，则阳常有余，而阴常不足。在天地，则天为阳，地为阴，而天则包乎地之外；在人身，则气为阳，血
为阴，而气实统乎血之先。一岁三百六十日，天日光明，则三百日而有余。夫光明者阳也，雨湿者阴也，阳有
余而阴不足，此其征也。人与天地相参，与日月相应，亦当阳气有余。盖阳主气而阴主血，如人阴血暴脱，
阳气犹存，不致殒命；如阳气一脱，阴血虽充，难延旦夕。苟能于阴阳之中，而知阳重于阴，则遇病施治，自
有生机，凉泻杀人，吾知免夫！
部位者，头、面、胸、背、胁、腹、手、足，各有所属之
部、所主之位也。
头为三阳之首，三阳者太阳也，自印堂，至额颅，上巅顶，从脑下项，皆足太阳经脉之部，故曰头为三阳
之首也。两颧属肾，《刺热论》云∶色荣颧骨，其热内连肾也。两目为肝之窍，而五脏精华皆注于目，故瞳神
属肾，黑眼属肝，白眼属肺，内外 肉属心，眼包属脾，两鼻为肺窍，而位居中央，又属乎脾。鼻内口鼻交通
之处，则为颃颡，又为蓄门，乃肝、肺相交之部也。口为脾窍，内外唇肉，脾所主也。舌为心苗，齿为骨余，
而齿龈则为牙床，又属乎胃。舌之下，腮之内，为廉泉、玉英，乃水液之上源也。耳为肾窍，又心亦开窍于耳。
胃足阳明之脉，起于鼻交 中，循鼻外，入齿中，挟口环唇。胆足少阳之脉，起于目锐 ，上抵头角，循耳后，
入耳中，出走耳前。此头面之部位，各有所属也。
头面以下，前有咽喉，后有颈项。喉居右，咽居左，喉为气管而硬，咽为食管而软。咽喉之中，则为吭嗌，
吭嗌之上，则为舌本，舌本居下 之尽，而上 之尽，则有小舌，所谓会厌也。太阴脾脉络舌本，少阴肾脉络
舌本，阳阴胃脉络舌本。咽喉之外，则有动脉，居乎两旁，所谓人迎之脉，乃胃足阳明之脉也。人迎之下，锁
骨空处，则为缺盆，肺所主也。又阳明经脉行身之前，自面部而至胸膈，皆阳明经脉所主也。缺盆之下，两乳之
上，谓之膺中。膺中之中，谓之上膈，即上焦也。经云∶
上焦开发，宣五谷味，熏肤充身泽毛，若雾露之溉也。上膈而下，谓之膈中，即胸膈也。胸膈之间，谓之膻中；
膻中，即心包络也。心包主血、主脉，横通四布。包络之下，即有胃络，两络相通，而横布于经脉之间。
胸乃心主之宫城，而包络包乎心之外；肺为五脏之长，而盖乎心之上。心窝之下，谓之中焦。胃有三脘∶上焦
之旁，即上脘也；中焦之旁，即中脘也；下焦之旁，即下脘也。头面之下，后有颈项。项之中央，名为风府；
项之两旁，名为风池。项下高耸大椎，乃脊骨之第一椎。自脊骨而下，至七节之两旁，名为鬲俞。经云∶七
节之旁，中有小心。以明鬲俞之穴，乃心气之游行出入。而太阳经脉，行身之背。此胸背之部位，各有所属也。
胸膈之下，腹也。胸膈下侧，胁也。前胸后背，而胁则居胸背之间，行身之侧。胁之上为腋，胁之下为季
胁。太阳行身之背，而主开；阳明行身之前，而主阖；少阳行身之侧，而主枢。舍开则不能阖，舍阖则不能开。
舍枢则不能为开阖，是枢者乃开阖之关键也。大腹名为坤土；坤土，太阴之脾土也。大腹之上，下脘之间，为
中土；中土，阳明之胃土也。大肠名回肠，盘旋于腹之左右。小肠居大肠之前，脐乃小肠之总结。而贴脐左
右，乃冲脉所出。经云∶冲脉于脐左右之动脉者是也。脐之下，则为小腹。小腹两旁，名为少腹。小腹者，少
阴水脏、膀胱水腑之所属也。少腹者，厥阴肝脏，胞中
血海之所居也。血海居膀胱之外，名曰胞中，膀胱居血海之内，故曰∶膀胱者，胞之室也。从小腹而入前阴，
乃少阴、太阴、阳明三经之属。经云∶肾开窍于前后二阴，是前阴者，属少阴也。经云∶前阴者，宗筋之所聚，
太阴、阳明之所合也。又阳明主润宗筋。是前阴又属太阴、阳明也。阴囊卵核，乃厥阴肝经之所属，故经云∶
厥阴病，则舌卷囊缩。舌卷，手厥阴；囊缩，足厥阴也。又云∶厥阴气绝，则卵上缩而终。此胁腹之部位，
各有所属也。
两手、两足曰四肢。两手之上，则有肘、腋；两足之上，则有 、髀。两肘、两腋、两 、两髀，名曰
八。从臂至手，乃手太阴肺金所出，而兼手少阴、厥阴。此手之三阴，从胸走手也。从足至股，乃足太阴脾
经所出，而兼足少阴、厥阴。此足之三阴，从足走胸也。夫手足三阴三阳十二经脉，交相通贯，行于周身。
手之三阴，从胸走手；手之三阳，从手走头∶是手三阴、三阳，而循行于手臂矣。足之三阳，从头走足；足之
三阴，从足走胸∶是足三阴、三阳，而循行于足股矣。此手足之部位，各有所属也。
《灵枢》十二经脉，行于周身，虽详言之，而医未之悉也。今举其概而约言之，手太阴肺脉，起于中焦，
横出腋下，循臂内，出手大指次指，而交于手阳明之大
肠。大肠之脉，起于手大指之次指，循臂外，入缺盆，上面，挟鼻孔，而交于足阳明胃脉。胃脉起于鼻 中，
至额颅，循喉咙，下膈，挟脐，入膝膑，下足跗，出足大指，而交于足太阴之脾脉。脾脉起于足大指，上膝
股之前，入腹，上膈，连舌本，注心中，而交于手少阴之心脉。心脉起于心中，上肺，挟咽，出腋，下循 内，
抵掌骨，出小指之内，而交于手太阳之小肠。小肠之脉，起于手小指，出手踝，循 外，交肩上，入耳中，
至目内 ，而交于足太阳之膀胱。膀胱之脉，起于目内 ，从头下项脊，循背膂，下腿后，至足小指外侧，而
交于足少阴之肾脉。肾脉起于足小指，循足心，上 股，贯脊，上贯肝膈，入肺，挟舌本，注胸中，而交于手
厥阴之心包。心包之脉，起于胸中，循胸，出胁，入肘，循臂，过掌中，循小指之次指，而交于手少阳之三焦。
三焦脉起于手小指之次指，循手臂，出臂外，贯肘，上肩，入耳中，出耳前后，至目锐 ，而交于足少阳之
胆脉。胆脉起于目锐 ，从耳后至肩，合缺盆，下胸中，过季胁，出膝，循足跗，出足大指，而交于足厥阴之
肝脉。肝脉起于足大指丛毛之际，从 股而上，过阴器，抵小腹，上入胸中，而交于手太阴之肺脉。是为十二
经脉之一周，乃头面胸背手足，各有所属，而为周身之部位也。
水是阴，火是阳。在水与火之中，火尤为重要。因为水属于阴，阴本身不能化生生命，必须借助火的阳气才能产生生机。所以水必须借助火加热后才能饮用，食物必须借助火烹煮后才能食用。在地面上表现为水，在天空中对应为寒；在地面上表现为火，在天空中对应为热。阳热之气能够孕育万物，如果遇到阴寒之气，万物就会死亡。医生若能在水火关系中懂得权衡轻重之理，那么救治存活的人就多，致死的情况就少了。
《内经》说：阴阳这两个概念，只有名称而没有具体的形态。数量可以推演到十，再推演可以到百；推到千，再推到万；即使达到万的程度，也无法穷尽。试着从大体上来论述，那就是阳气常常有余，而阴气常常不足。在天地之间，天属阳，地属阴，而天包裹在地的外面；在人体中，气属阳，血属阴，而气实际上统领在血之前。一年三百六十天，天气光明的时候有三百多天。所谓光明就是阳，雨湿就是阴，阳有余而阴不足，这就是征象。人与天地相参合，与日月相应，也应当是阳气有余。大概因为阳主司气，阴主司血，假如人的阴血突然大量脱失，只要阳气尚存，就不会立即死亡；假如阳气一旦脱失，即使阴血充足，也难以维持到第二天早晨。如果能在阴阳之中懂得阳气重于阴气，那么遇到疾病进行治疗时，自然会有生机，那些滥用寒凉泻下之法杀人的情况，我想是可以避免的了！
部位，是指头、面、胸、背、胁、腹、手、足，各自有所归属的部位和所主宰的位置。
头部是三阳经的首领。三阳经中的太阳经，自印堂穴起，经过额颅，到达头顶，再从脑后下行至项部，都是足太阳膀胱经脉所经过的部位，所以说头是三阳经的首领。两颧骨归属于肾，《刺热论》说：面色红润显现于颧骨，说明热邪内部连及肾脏。两眼是肝的窍道，而五脏的精气都灌注于眼睛，所以瞳孔归属于肾，黑眼球（黑睛）归属于肝，白眼珠（白睛）归属于肺，内外眦的肉（胞睑/眼胞）归属于心，眼睑归属于脾。两个鼻孔是肺的窍道，且位居面部中央，又归属于脾。鼻腔内口鼻相通的地方，称为颃颡（háng sǎng，鼻咽部），也称为蓄门，这是肝与肺经气相交的部位。口是脾的窍道，内外的唇肉由脾所主宰。舌是心的苗窍，牙齿是骨骼的余气，而牙龈则是牙床，又归属于胃。舌头下方、腮部之内，是廉泉穴和玉英穴所在，这是水液上行的源头。耳朵是肾的窍道，同时心也开窍于耳。足阳明胃经的经脉，起于鼻翼旁的迎香穴，交会于鼻根，沿鼻外侧下行，进入齿龈中，环绕口唇。足少阳胆经的经脉，起于目外眦瞳子髎穴，向上到达头角，沿耳后下行，进入耳中，走出耳前。这些头面部的部位，各有其所属的经络脏腑。
头面以下，前面有咽喉，后面有颈项。喉位于右侧，咽位于左侧，喉是气管且质地较硬，咽是食管且质地较软。咽喉中间，称为吭嗌（kēng yì，咽喉深处），吭嗌之上，称为舌本（舌根），舌本位于下颌骨的尽头，而上颌骨的尽头，有小舌，也就是会厌。足太阴脾经的络脉联系舌本，足少阴肾经的络脉联系舌本，足阳明胃经的络脉联系舌本。咽喉的外侧，有动脉搏动，位于两旁，这就是人迎脉，属于足阳明胃经的经脉。人迎脉之下，锁骨窝处，称为缺盆，由肺所主宰。另外，阳明经脉行走在身体前面，自面部直到胸膈，都属于阳明经脉所主宰的范围。缺盆之下，两乳之上，称为膺中。膺中的中部，称为上膈，即上焦。《内经》说：上焦开发，宣发五谷的气味，熏蒸皮肤，充实身体，润泽毫毛，就像雾露灌溉一样。上膈之下，称为膈中，即胸膈。胸膈之间，称为膻中；膻中，就是心包络。心包主司血，主司脉，横向通达，分布四周。心包络之下，就有胃的络脉，两条络脉相通，横向分布在经脉之间。胸部是心主（心脏）的宫城，而心包络包裹在心脏的外面；肺是五脏之长，覆盖在心脏的上面。心窝之下，称为中焦。胃分为三个脘：上焦的旁边，就是上脘；中焦的旁边，就是中脘；下焦的旁边，就是下脘。头面之下，后面有颈项。颈项的中央，名为风府穴；颈项的两旁，名为风池穴。颈下高耸的大椎穴，是脊骨的第一节椎骨。从脊骨向下，到第七节椎骨的两旁，名为膈俞穴。《内经》说：第七节椎骨的旁边，中有小心。以此说明膈俞穴，是心气游行出入的地方。而足太阳膀胱经脉，行走在身体的背部。这些胸背部的部位，各有其所属。
胸膈之下，是腹部。胸膈的侧面，是胁部。前胸后背，而胁部位于胸背之间，行走在身体的侧面。胁的上方为腋窝，胁的下方为季胁。足太阳膀胱经行走在身体背部，主司“开”；足阳明胃经行走在身体前面，主司“阖”；足少阳胆经行走在身体侧面，主司“枢”。舍弃了“开”就不能实现“阖”，舍弃了“阖”就不能实现“开”。舍弃了“枢”就不能完成开阖的功能，所以“枢”是开阖的关键。大腹被称为坤土；坤土，指的是太阴脾土。大腹之上，下脘之间，为中土；中土，指的是阳明胃土。大肠名叫回肠，盘旋在腹部的左右两侧。小肠位于大肠的前面，肚脐是小肠的总结之处。而在肚脐贴着的左右两侧，是冲脉发出的地方。《内经》说：冲脉就是在脐左右有动脉搏动的地方。脐之下，就是小腹。小腹的两旁，名为少腹。小腹，是少阴水脏（肾）和水腑（膀胱）所属的区域。少腹，是厥阴肝脏和胞中（血海）居住的地方。血海居住在膀胱之外，名叫胞中，膀胱居住在血海之内，所以说：膀胱，是胞的居室。从小腹进入前阴，是少阴、太阴、阳明三条经脉所属。《内经》说：肾开窍于前后二阴，所以前阴归属于少阴。《内经》说：前阴，是宗筋汇聚的地方，是太阴和阳明经气会合之处。另外阳明经主司滋润宗筋。所以前阴又归属于太阴和阳明。阴囊和睾丸，是足厥阴肝经所属，所以《内经》说：厥阴病，会出现舌头卷缩和阴囊收缩。舌卷，涉及手厥阴心包经；囊缩，涉及足厥阴肝经。又说：厥阴经气断绝，就会出现睾丸上缩直至死亡。这些胁腹部的部位，各有其所属。
两手、两足称为四肢。两手的上部，有肘、腋；两足的上部，有腘（guó，膝后弯处）、髀（bì，大腿）。两肘、两腋、两腘、两髀，称为八虚。从手臂到手，是手太阴肺金经发出，兼涉手少阴心和手厥阴心包经。这三条手三阴经，从胸部走向手部。从脚到大腿，是足太阴脾经发出，兼涉足少阴肾和足厥阴肝经。这三条足三阴经，从足部走向胸部。手足三阴三阳共十二条经脉，交错相通贯串，行走在全身。手之三阴经，从胸走手；手之三阳经，从手走头：这是手三阴、手三阳，循行于手臂。足之三阳经，从头走足；足之三阴经，从足走胸：这是足三阴、足三阳，循行于足和大腿。这些手足部位的经络，各有其所属。
《灵枢》中详细论述了十二经脉行走在周身，但医生们未必完全知晓。现在列举其概要并简要说明：手太阴肺经，起于中焦，横向走出腋下，沿臂内侧下行，出于大拇指和第二指之间，交于手阳明大肠经。大肠经的经脉，起于手第二指，沿臂外侧上行，进入缺盆，上面部，挟鼻孔，交于足阳明胃经。胃经起于鼻根旁，至额颅，沿喉咙下行，穿过膈肌，挟脐两旁，入膝盖髌骨，下至足背，出于足大趾，交于足太阴脾经。脾经起于足大趾，上行至膝股前侧，进入腹部，上行穿过膈肌，连接舌本，注入心中，交于手少阴心经。心经起于心中，上行至肺，挟咽喉，出于腋下，沿臂内侧下行，抵手掌骨，出于小指内侧，交于手太阳小肠经。小肠经起于手小指，出手腕，沿臂外侧上行，交于肩上，进入耳中，至目内眦，交于足太阳膀胱经。膀胱经起于目内眦，从头下项脊，沿背部脊柱旁下行，过腿后侧，至足小趾外侧，交于足少阴肾经。肾经起于足小趾，沿足心，上行过大腿，贯穿脊柱，上行穿过肝膈，进入肺，挟舌本，注入胸中，交于手厥阴心包经。心包经起于胸中，沿胸前行，出于胁肋，进入肘中，沿臂下行，过掌心，沿小指和第二指之间，交于手少阳三焦经。三焦经起于手小指和第二指之间，沿手臂上行，出臂外侧，贯穿肘部，上肩，入耳中，出耳前后，至目外眦，交于足少阳胆经。胆经起于目外眦，从耳后到肩，汇合于缺盆，下入胸中，过季胁，出膝部，沿足背下行，出于足大趾，交于足厥阴肝经。肝经起于足大趾丛毛处，从大腿内侧上行，过生殖器，抵小腹，上行入胸中，交于手太阴肺经。这是一周十二经脉的循环，也就是头面胸背手足各有所属，构成了周身的部位网络。
Water is Yin, and Fire is Yang. Among water and fire, fire is particularly important. This is because water belongs to Yin; Yin alone cannot generate life but must rely on the Yang Qi of fire to produce vitality. Therefore, water must be heated by fire before it can be drunk, and food must be cooked by fire before it can be eaten. On earth, it manifests as water; in heaven, it corresponds to cold. On earth, it manifests as fire; in heaven, it corresponds to heat. The warm and hot Yang Qi can nurture all things, but if it encounters Yin-cold Qi, all things will perish. If a physician can understand the principle of weighing priorities within the relationship between water and fire, then there will be more lives saved and fewer deaths.
The *Classic* states: "Yin and Yang have names but no specific form." Their numbers can be extended to ten, then to a hundred; to a thousand, then to ten thousand; even reaching ten thousand, they are incalculable. Speaking generally, Yang is often in excess, while Yin is often deficient. In the cosmos, Heaven is Yang and Earth is Yin, with Heaven enveloping Earth. In the human body, Qi is Yang and Blood is Yin, with Qi actually leading Blood. In a year of 360 days, the sun shines brightly for over 300 days. Brightness represents Yang, while rain and dampness represent Yin. Yang being in excess and Yin being deficient is the evidence. Humans correspond to Heaven and Earth and resonate with the Sun and Moon, so their Yang Qi should also be in excess. Generally, Yang governs Qi and Yin governs Blood. If a person suffers sudden massive loss of Yin Blood, as long as Yang Qi remains, death will not occur immediately. However, if Yang Qi escapes, even if Yin Blood is abundant, life cannot be sustained until dawn. If one understands that Yang is heavier than Yin within the balance of Yin and Yang, then when treating diseases, there will naturally be hope for survival, and I believe we can avoid the fatal errors caused by indiscriminate use of cooling and purging methods!
"Locations" refer to the head, face, chest, back, flanks, abdomen, hands, and feet, each having its specific region and governing position.
The head is the leader of the Three Yang meridians. The Taiyang (Greater Yang) meridian starts from the Yintang point, passes through the forehead and vertex, descends from the brain to the nape, covering the areas of the Foot-Taiyang Bladder Meridian, hence the head is called the leader of the Three Yang. The cheekbones belong to the Kidney. The *Treatise on Acupuncture and Heat* states: "When redness appears on the cheekbones, the heat internally connects to the Kidney." The eyes are the orifices of the Liver, and the essence of the Five Zang organs pours into them. Thus, the pupil belongs to the Kidney, the black part (cornea/iris area) belongs to the Liver, the white part (sclera) belongs to the Lungs, the inner and outer canthi (palpebral caruncle/canthi) belong to the Heart, and the eyelids belong to the Spleen. The nostrils are the orifices of the Lungs, located centrally, and thus also belong to the Spleen. The passage connecting the nose and mouth inside the nasal cavity is called the *hangsang* (nasopharynx), also known as the storage gate, which is the area where Liver and Lung Qi intersect. The mouth is the orifice of the Spleen, and the inner and outer lips are governed by the Spleen. The tongue is the sprout of the Heart; teeth are the surplus of bones, and the gums (dental alveoli) belong to the Stomach. Below the tongue and inside the cheeks lie the Lianquan and Yuying points, which are the upper sources of body fluids. The ears are the orifices of the Kidneys, and the Heart also opens into the ears. The Foot-Yangming Stomach Meridian originates at Yingxiang beside the nose, crosses the nasal root, runs down the lateral side of the nose, enters the gum, and circles the lips. The Foot-Shaoyang Gallbladder Meridian originates at Tongziliao at the outer canthus, ascends to the temporal angle, runs behind the ear, enters the ear, and emerges anterior to the ear. These locations on the head and face each have their specific affiliations.
Below the head and face, there is the throat and pharynx in front, and the neck at the back. The larynx (throat/trachea) is on the right, and the pharynx (esophagus) is on the left. The larynx is the airway and is hard; the pharynx is the food pipe and is soft. Between the throat and pharynx lies the deep throat (*kengyi*), above which is the root of the tongue. The root of the tongue is at the end of the mandible, while the epiglottis is at the end of the maxilla. The collaterals of the Foot-Taiyin Spleen Meridian connect to the root of the tongue, as do those of the Foot-Shaoyin Kidney Meridian and the Foot-Yangming Stomach Meridian. Outside the throat and pharynx, on both sides, lies the Renying pulse (carotid artery), which belongs to the Foot-Yangming Stomach Meridian. Below Renying, in the hollow of the clavicle, is the Quepen point, governed by the Lungs. Furthermore, the Yangming meridians run along the anterior body, from the face to the chest-diaphragm area, all governed by the Yangming meridians. Below Quepen and above the breasts is the Yingzhong. The center of Yingzhong is called Shangge (Upper Diaphragm), which is the Upper Jiao. The *Classic* states: "The Upper Jiao opens and develops, distributing the flavors of grains, steaming the skin, filling the body, and moistening the hair, like mist and dew." Below Shangge is Gezhong, i.e., the chest-diaphragm. Between the chest and diaphragm is Danzhong, which is the Pericardium (Xinbao). The Pericardium governs Blood and vessels, extending horizontally and spreading everywhere. Below the Pericardium are the stomach collaterals, connected and spread horizontally among the meridians. The chest is the palace city of the Heart Master, with the Pericardium enveloping the Heart externally. The Lungs are the chief of the Five Zang, covering the Heart superiorly. Below the heart pit is the Middle Jiao. The Stomach has three wans (parts): next to the Upper Jiao is the Shangwan (Upper Wan); next to the Middle Jiao is the Zhongwan (Middle Wan); next to the Lower Jiao is the Xiawan (Lower Wan). Behind the head and face is the neck. The center of the neck is Fengfu; the sides are Fengchi. The prominent Dazhui below the neck is the first vertebra of the spine. From the spine downward, to the sides of the seventh vertebra, is the Geshu point. The *Classic* states: "Beside the seventh vertebra lies the Xiao Xin (Minor Heart)," indicating that Geshu is the pathway for Heart Qi circulation. The Foot-Taiyang Bladder Meridian runs along the back. These chest and back locations each have their specific affiliations.
Below the chest-diaphragm is the abdomen. The sides of the chest-diaphragm are the flanks. The flanks are situated between the anterior chest and posterior back, running along the lateral body. Above the flank is the axilla; below is the hypochondrium. The Foot-Taiyang Bladder Meridian runs along the back and governs "Opening"; the Foot-Yangming Stomach Meridian runs along the front and governs "Closing"; the Foot-Shaoyang Gallbladder Meridian runs along the side and governs the "Pivot." Without Opening, Closing cannot occur; without Closing, Opening cannot occur. Without the Pivot, Opening and Closing cannot function; thus, the Pivot is the key to Opening and Closing. The large abdomen is called Kun Earth, referring to the Taiyin Spleen Earth. Above the large abdomen, between the lower wan, is Middle Earth, referring to the Yangming Stomach Earth. The Large Intestine, named Hui Chang (coiled intestine), spirals on the left and right of the abdomen. The Small Intestine is in front of the Large Intestine, and the umbilicus is the summary point of the Small Intestine. Adjacent to the left and right of the umbilicus is the origin of the Chong Mai (Penetrating Vessel). The *Classic* states: "The Chong Mai is the arterial pulse on the left and right of the umbilicus." Below the umbilicus is the lower abdomen. The sides of the lower abdomen are called Shaofu. The lower abdomen belongs to the Shaoyin Water Zang (Kidney) and Water Fu (Bladder). The Shaofu is the residence of the Jueyin Liver and the Baozhong (Sea of Blood). The Sea of Blood resides outside the Bladder, named Baozhong; the Bladder resides inside the Sea of Blood. Hence, it is said: "The Bladder is the chamber of the Baozhong." Entering the anterior yin from the lower abdomen belongs to the Shaoyin, Taiyin, and Yangming meridians. The *Classic* states: "The Kidney opens into the anterior and posterior yin," so the anterior yin belongs to Shaoyin. The *Classic* also states: "The anterior yin is the gathering place of the Zongjin (tendons), where Taiyin and Yangming combine." Additionally, Yangming moistens the Zongjin. Thus, the anterior yin also belongs to Taiyin and Yangming. The scrotum and testicles belong to the Foot-Jueyin Liver Meridian. Hence, the *Classic* states: "In Jueyin disease, the tongue curls and the scrotum retracts." Tongue curling involves the Hand-Jueyin Pericardium; scrotal retraction involves the Foot-Jueyin Liver. It is also said: "When Jueyin Qi perishes, the testicles retract upward, leading to death." These flank and abdominal locations each have their specific affiliations.
The two hands and two feet are called the Four Limbs. Above the hands are the elbows and axillae; above the feet are the popliteal fossae (Guo) and thighs (Bi). The two elbows, two axillae, two popliteal fossae, and two thighs are called the Eight Xu (Empty/Vulnerable spots). From the arm to the hand, the Hand-Taiyin Lung Metal Meridian originates, involving the Hand-Shaoyin Heart and Hand-Jueyin Pericardium. These three Hand-Yin meridians travel from the chest to the hands. From the foot to the thigh, the Foot-Taiyin Spleen Meridian originates, involving the Foot-Shaoyin Kidney and Foot-Jueyin Liver. These three Foot-Yin meridians travel from the feet to the chest. The Twelve Primary Meridians of the Hand and Foot, consisting of Three Yin and Three Yang, interconnect and circulate throughout the body. The Hand-Yin meridians go from chest to hand; the Hand-Yang meridians go from hand to head—thus, Hand Yin and Yang circulate in the arms. The Foot-Yang meridians go from head to foot; the Foot-Yin meridians go from foot to chest—thus, Foot Yin and Yang circulate in the legs and thighs. These hand and foot locations each have their specific affiliations.
The *Ling Shu* details the Twelve Primary Meridians circulating throughout the body, yet physicians may not fully comprehend them. Here is a summary: The Hand-Taiyin Lung Meridian originates in the Middle Jiao, exits laterally under the axilla, follows the medial aspect of the arm, emerges between the thumb and index finger, and connects with the Hand-Yangming Large Intestine Meridian. The Large Intestine Meridian originates at the radial side of the index finger, follows the lateral aspect of the arm, enters the Quepen (supraclavicular fossa), ascends to the face, runs alongside the nostrils, and connects with the Foot-Yangming Stomach Meridian. The Stomach Meridian originates at the nasal root, reaches the forehead, follows the throat, descends through the diaphragm, runs alongside the umbilicus, enters the knee patella, descends to the dorsum of the foot, emerges at the big toe, and connects with the Foot-Taiyin Spleen Meridian. The Spleen Meridian originates at the big toe, ascends anterior to the knee and thigh, enters the abdomen, ascends through the diaphragm, connects to the root of the tongue, injects into the Heart, and connects with the Hand-Shaoyin Heart Meridian. The Heart Meridian originates in the Heart, ascends to the Lungs, runs alongside the pharynx, exits the axilla, follows the medial aspect of the arm, reaches the palm bone, emerges at the ulnar side of the little finger, and connects with the Hand-Taiyang Small Intestine Meridian. The Small Intestine Meridian originates at the ulnar side of the little finger, exits the wrist, follows the lateral aspect of the arm, connects at the shoulder, enters the ear, reaches the inner canthus, and connects with the Foot-Taiyang Bladder Meridian. The Bladder Meridian originates at the inner canthus, descends from the head through the neck and spine, follows the paraspinal muscles, descends the posterior leg, reaches the lateral side of the little toe, and connects with the Foot-Shaoyin Kidney Meridian. The Kidney Meridian originates at the little toe, follows the sole of the foot, ascends through the thigh, penetrates the spine, ascends through the liver and diaphragm, enters the Lungs, runs alongside the root of the tongue, injects into the chest, and connects with the Hand-Jueyin Pericardium Meridian. The Pericardium Meridian originates in the chest, follows the chest, exits the costal region, enters the elbow, follows the arm, passes through the palm, follows between the little and index fingers, and connects with the Hand-Shaoyang Sanjiao Meridian. The Sanjiao Meridian originates between the little and index fingers, follows the arm, exits the lateral aspect of the arm, penetrates the elbow, ascends to the shoulder, enters the ear, emerges anterior and posterior to the ear, reaches the outer canthus, and connects with the Foot-Shaoyang Gallbladder Meridian. The Gallbladder Meridian originates at the outer canthus, goes from behind the ear to the shoulder, converges at Quepen, descends into the chest, passes the hypochondrium, emerges at the knee, follows the dorsum of the foot, emerges at the big toe, and connects with the Foot-Jueyin Liver Meridian. The Liver Meridian originates at the pubic hair of the big toe, ascends through the medial thigh, passes the genitalia, reaches the lower abdomen, ascends into the chest, and connects with the Hand-Taiyin Lung Meridian. This completes one cycle of the Twelve Primary Meridians, demonstrating that the head, face, chest, back, hands, and feet each have specific affiliations, forming the network of bodily locations.