一难曰∶十二经皆有动脉，独取寸口，以决五脏六腑死生吉凶之法，何谓也？
首发一难，问手足十二经皆有动脉，何以独取寸口以决死生，以起下文之义。
按∶五脏六腑之气，昼夜循环，始于肺而终于肺，是肺为一身之主气，而寸口乃肺之动脉，
在太渊、经渠之分，为脉之大会，故越人独取此以候五脏六腑之气。然诸经动脉，不可不知，
否则握手不及足，难免长沙之呵斥矣。手阳明大肠脉动合谷，（在手大指次指歧骨间。）手少阴心脉动极
泉，（在臂内腋下筋间。）手太阳小肠脉动天窗，（在颈侧大筋间曲颊下。）手少阳三焦脉动和 ，
（在耳兑发陷中。）手厥阴心包络脉动劳宫，（在掌中屈中指无名指尽处是。）足太阳膀胱脉动委中，（在膝
约纹里。）足少阴肾脉动太溪，（在足踝后跟骨上。）足太阴脾脉动冲门，（在曲骨旁，同身寸之三
寸五分。）足阳明胃脉动冲阳，（在足大指次指陷中为内庭，上内庭同身寸五寸是。）足厥阴肝脉动太
冲，（在足大指本节后，同身寸二寸是。）足少阳胆脉动听会。（在耳前陷中。）考《明堂针灸图》、
《甲乙经》诸书，指称动脉者二十余穴，惟此十余穴，或可用以诊候，而此十余穴中，又以太溪、冲阳、
太冲三足脉为扼要也。
然∶寸口者，脉之大会，手太阴之脉动也。
然，答辞。会，聚也。手太阴，肺之经，言肺主气，十二经之脉动，皆肺气鼓之，故肺朝百
脉，而大会于寸口。寸口者，即《素问·经脉别论》气口成寸，以决死生之义，故曰寸口。寸
口三部，鱼际为寸，太渊之高骨为关，经渠为尺，是手太阴肺经之动脉也。人之饮食入胃，其
清气上注于肺，以应呼吸，而行脉度，越人立问之意，所以独取夫寸口，而后世宗之，为不易
之法，四十五难脉会太渊，亦此义也。
人一呼脉行三寸，一吸脉行三寸，呼吸定息，脉行六寸。人一日一夜，凡一一万三千五百息，
脉行五十度周于身。漏水下百刻，荣卫行阳二十五度，行阴亦二十五度，为一周也，故五十度复会
于手太阴，寸口者，五脏六腑之所终始，故法取于寸口也。
此承上文言，人谓平人，不病而息数调匀者也。《灵枢·五十营篇》漏水下百刻，以分昼夜，
人一呼脉再动，气行三寸，一吸脉亦再动，气行三寸，呼吸定息，气行六寸，十息气行六尺，
二百七十息，气行十六丈二尺，气行一周于身，水下二刻，二千七百息，气行十周于身，水下
二十刻，一万三千五百息，气行五十营于身，水下百刻，凡行八百一十丈。《营卫生会篇》∶人
受气于谷，谷入于胃，以传于肺，其清者为营，浊者为卫，营在脉中，卫在脉外；营周不休，五
十度而复大会，卫与营俱行阳二十五度，行阴二十五度，一周也，故亦五十度而复大会于手太
阴矣。《素问·平人气象论》∶人一呼脉再动，一吸脉再动，呼吸定息，脉五动，闰以太息，命
曰平人。是脉者，营气也。行经脉一日五十周，今日平旦始于手太阴之寸口，明日平旦又会于
手太阴之寸口，此五脏六腑之所终始，故取法于寸口也。
按∶脉者，血中之气也，经言营气，取营运于中之义。西医言食入于胃至小肠，皆有微丝管
吸其精液，上至颈会管，过肺入心左上房，（心体中空，四壁嶙峋，或凹或凸，中有直肉隔之，故称左房右
房；左右半截，又有横肉间之，以分上下，筋丝数条牵连，故自能开阖，以应呼吸也。）化赤为血，
此即清者为营也。其血从左上房落左下房，入总脉管，由脊之膂筋，循行经脉之间，一日夜五十度周于身，
尽八百十丈之脉道，以应呼吸。漏下者，营气也。若夫卫气，取卫护于外之义，经脉中之血气，
由脉管之尾，出诸气街，入微丝血管，（经谓孙络者是也。）与阳明之悍气（人之饮食，五味杂投，奚能无毒，
西医谓之炭气者，此也。）相合，散布通体皮腠之间，充肤热肉，淡渗毫毛，此即浊者为卫也。脉管之
赤血，既入微丝血管，合阳明悍气，则其色渐变渐紫，西医因其有毒，谓之炭气。散布遍体，渐并
渐粗，而接入回血管（经谓络脉者是也。）之尾，血入回血管，内而脏腑，外而经脉并脉管，交相逆
顺而行。外行经脉者，有阴阳之别，一支浮于肌腠之上。一支沉于分肉之间，即阳络行于皮表，阴络行于皮
里，而皆与脉管偕行，经言营行脉中，卫行脉外者是也。回血管内外行遍，入总回
管，至心右上房，落右下房，递入于肺，呼出悍气，吸入生气，其血复化为赤，入心左上房，
阴阳相贯，如环无端者，此之谓也。然气中有血，血中有气，气与血不可须臾之相离，乃阴阳
互根，自然之理也。夫营运经脉中之血气，周夜行五十周者，如月之应水，流贯地中，其行疾。
出诸气街，合阳明悍气，缠布周身之血气，昼夜行一周者，如日随天道，绕地环转，其行迟，
故人与天地参也。行阴行阳者，阴络阳络中血气随经脉偕之卫气也。至若外邪袭人，热伤气，
寒伤血，当责诸孙络缠布周身之卫气。伏气内发，当责诸络脉中之卫气。浮于脉外者，可刺之
以泄其气，沉于脉内者，宜急攻以杀其毒。诊脉察病，当责诸营运脉管之营气。盖血入心之上
房，落下房，过总脉管，皆开阖声与呼吸相应，故可候脉之动数，而西医听声以辨心疾，亦取
乎此。
第一难说：十二经脉都有搏动的动脉，为什么唯独选取寸口脉，作为判断五脏六腑生死吉凶的方法呢？
开篇提出第一难，询问手足十二经皆有动脉，为何唯独取寸口来判断生死，以此开启下文的意义。
按语：五脏六腑的气，昼夜循环不息，始于肺而终于肺，所以肺是全身主气之脏，而寸口正是肺的动脉，位于太渊、经渠穴之间，是脉气大会聚之处，所以越人（扁鹊）唯独选取此处来诊察五脏六腑之气。然而其他经脉的动脉，也是不可不知的，否则只摸手腕而不及足部，难免受到长沙太守张仲景的呵斥。手阳明大肠经的动脉在合谷穴，（位于手大指与食指歧骨间。）手少阴心经的动脉在极泉穴，（位于臂内侧腋下筋间。）手太阳小肠经的动脉在天窗穴，（位于颈侧大筋间曲颊下。）手少阳三焦经的动脉在和髎穴，（位于耳前发际凹陷中。）手厥阴心包络经的动脉在劳宫穴，（位于掌心中，屈中指、无名指指尖尽处即是。）足太阳膀胱经的动脉在委中穴，（位于膝腘窝横纹中。）足少阴肾经的动脉在太溪穴，（位于足内踝后方跟骨上方。）足太阴脾经的动脉在冲门穴，（位于曲骨旁，同身寸三寸五分处。）足阳明胃经的动脉在冲阳穴，（位于足大指与次指陷中为内庭穴，内庭穴向上同身寸五寸处即是。）足厥阴肝经的动脉在太冲穴，（位于足大指本节之后，同身寸二寸处即是。）足少阳胆经的动脉在听会穴。（位于耳前凹陷中。）考证《明堂针灸图》、《甲乙经》等书籍，被称为“动脉”的穴位有二十多个，只有这十余个穴位，或许可以用来诊候，而这十余个穴位中，又以足部的太溪、冲阳、太冲这三处脉动最为关键扼要。
“然”，是回答的发语词。“会”，即汇聚之意。手太阴是肺之经脉，言肺主气，十二经脉的脉动，皆由肺气鼓动，所以说肺朝百脉，而脉气大会于寸口。寸口，即《素问·经脉别论》中所谓“气口成寸，以决死生”的含义，所以称为寸口。寸口分为三部，鱼际处为寸部，太渊穴的高骨处为关部，经渠处为尺部，这是手太阴肺经的动脉所在。人的饮食进入胃中，其清轻之气上注于肺，以配合呼吸，并运行脉度，越人设立此问的本意，在于唯独取法寸口，而后世都尊崇这一方法，视为不可更改的法度，《难经》第四十五难提到“脉会太渊”，也是这个道理。
人一呼，脉气运行三寸；一吸，脉气运行三寸；呼吸定息（一次完整的呼吸周期），脉气运行六寸。人一天一夜，共有一万三千五百次呼吸，脉气运行五十周遍全身。漏水滴下一百刻的时间，营气行于阳分二十五周，行于阴分二十五周，合为一周，所以五十周后再次会合于手太阴肺经。寸口，是五脏六腑气血终始之处，所以诊脉之法取法于寸口。
这段承接上文而言，所谓平人，是指不生病且呼吸调匀的人。《灵枢·五十营篇》记载：漏水滴下一百刻，用来划分昼夜。人一呼脉跳动两次，气行三寸；一吸脉也跳动两次，气行三寸；呼吸定息，气行六寸。十次呼吸，气行六尺；二百七十次呼吸，气行十六丈二尺，气行一周遍全身，水下两刻；二千七百次呼吸，气行十周遍全身，水下二十刻；一万三千五百次呼吸，气行五十营遍全身，水下百刻，总共行八百一十丈。《营卫生会篇》说：人受气于水谷，水谷进入胃中，传送给肺，其中清轻的部分成为营气，浊重的部分成为卫气，营气行于脉中，卫气行于脉外；营气周流不休，五十周后再次大会，卫气与营气都行于阳分二十五周，行于阴分二十五周，合为一周，所以也是五十周后再次会合于手太阴肺经。《素问·平人气象论》说：人一呼脉跳动两次，一吸脉也跳动两次，呼吸定息时脉跳动五次，加上偶尔的深长呼吸（太息），称为平人。这种脉象，反映的是营气。营气行于经脉中，一日运行五十周，今天清晨开始于手太阴肺经的寸口，明天清晨又会合于手太阴肺经的寸口，这是五脏六腑气血终始之处，所以诊脉取法于寸口。
按语：脉，是血中的气，经文所说的营气，取营运于脉中之义。西医认为食物进入胃至小肠，都有微细血管吸收其精液，上至颈静脉汇合处，经过肺部进入心脏左心房，（心脏体中空，四壁凹凸不平，或有凹或凸，中间有直肉隔开，故称左房右房；左右半截之间，又有横肉间隔，以分上下，筋丝数条牵连，故能自动开阖，以应呼吸。）化赤为血，这就是清者为营。血液从左心房流入左心室，进入总脉管，沿着脊柱的膂筋，循行于经脉之间，一天一夜五十周遍全身，走完八百一十丈的脉道，以应呼吸。漏下者，即营气。至于卫气，取卫护于外的意义，经脉中的血气，从脉管的末端，出于诸气街，进入微细血管，（经文所说的孙络即是。）与阳明经的悍气（人的饮食，五味杂投，怎能没有毒性，西医称之为炭气，指的就是这个。）相合，散布于全身皮腠之间，充实皮肤，温暖肌肉，淡渗毫毛，这就是浊者为卫。脉管中的赤血，既然进入微细血管，与阳明悍气相合，则颜色逐渐变紫，西医因其有毒，称之为炭气。散布遍体，逐渐合并变粗，而接入回血管（经文所说的络脉即是。）的末端，血液进入回血管，内至脏腑，外至经脉及脉管，交互逆顺而行。行于经脉之外的，有阴阳之别，一支浮于肌腠之上，一支沉于分肉之间，即阳络行于皮表，阴络行于皮里，而都与脉管并行，经文所说营行脉中，卫行脉外，即是此理。回血管内外行遍，汇入总回管，到达心脏右上房，落入右下房，递送入肺，呼出悍气，吸入生气，血液重新化为红色，进入心脏左心房，阴阳相互贯穿，如环无端，说的就是这种情况。然而气中有血，血中有气，气与血不可片刻分离，这是阴阳互根的自然道理。那营运于经脉中的血气，昼夜运行五十周，如同月亮应和水势，流贯地中，其行速快。出于诸气街，合于阳明悍气，缠布周身之血气，昼夜运行一周，如同太阳随天道，绕地环转，其行缓慢，所以人与天地参配。行阴行阳的，是指阴络阳络中的血气随着经脉偕同卫气运行。至于外邪侵袭人体，热伤气，寒伤血，应当责求于孙络缠布周身之卫气。伏气内发，应当责求于络脉中之卫气。浮于脉外的，可以针刺以泄其气；沉于脉内的，宜急攻以杀其毒。诊脉察病，应当责求于营运脉管之营气。因为血入心上房，落下房，过总脉管，都有开阖之声与呼吸相应，所以可以候察脉的动数，而西医听声以辨别心脏病，也是取法于此。
Chapter 1 states: All twelve meridians have pulsating arteries. Why is the Cun Kou (Cun-kou, pulse at the wrist) alone selected as the method to determine the life and death, auspiciousness and inauspiciousness of the Zang-Fu organs?
This initiates the first difficulty, asking why, given that all twelve hand and foot meridians have pulsating arteries, only the Cun Kou is taken to determine life and death, thereby setting up the meaning for the following text.
Commentary: The Qi of the five Zang and six Fu organs circulates day and night without cessation, starting from the Lung and ending at the Lung. Thus, the Lung is the master of Qi in the body, and the Cun Kou is the pulsating artery of the Lung. Located between the Taiyuan (LU9) and Jingqu (LU8) acupoints, it is the great gathering point of pulses. Therefore, Yue Ren (Bian Que) exclusively selects this location to observe the Qi of the five Zang and six Fu organs. However, the pulsating arteries of other meridians must not be unknown; otherwise, palpating only the wrist and neglecting the feet would inevitably incur the reprimand of Zhang Zhongjing (Changsha Taishou). The pulsating artery of the Hand-Yangming Large Intestine meridian is at Hegu (LI4), (located between the metacarpals of the thumb and index finger.) The pulsating artery of the Hand-Shaoyin Heart meridian is at Jiquan (HT1), (located in the tendon space under the axilla on the medial arm.) The pulsating artery of the Hand-Taiyang Small Intestine meridian is at Tianchuang (SI16), (located in the large tendon space on the side of the neck, below the angle of the jaw.) The pulsating artery of the Hand-Shaoyang Sanjiao meridian is at He'liao (TE22), (located in the depression anterior to the ear within the hairline.) The pulsating artery of the Hand-Jueyin Pericardium meridian is at Laogong (PC8), (located in the center of the palm, at the tip of the middle and ring fingers when flexed.) The pulsating artery of the Foot-Taiyang Bladder meridian is at Weizhong (BL40), (located in the transverse crease of the popliteal fossa.) The pulsating artery of the Foot-Shaoyin Kidney meridian is at Taixi (KI3), (located above the calcaneus behind the medial malleolus.) The pulsating artery of the Foot-Taiyin Spleen meridian is at Chongmen (SP15), (located beside Qugu, three cun five fen using the body-cun measurement.) The pulsating artery of the Foot-Yangming Stomach meridian is at Chongyang (ST42), (located in the depression between the first and second toes; Neiting (ST44) is here, and Chongyang is five cun above Neiting using the body-cun measurement.) The pulsating artery of the Foot-Jueyin Liver meridian is at Taichong (LR3), (located posterior to the first metatarsophalangeal joint, two cun using the body-cun measurement.) The pulsating artery of the Foot-Shaoyang Gallbladder meridian is at Tinghui (GB2). (Located in the depression anterior to the ear.) Consulting texts such as *Mingtang Acupuncture and Moxibustion Diagrams* and *Jia Yi Jing*, there are over twenty acupoints referred to as "arteries." Among these, only about ten can be used for diagnosis, and among these ten, the pulses at Taixi (KI3), Chongyang (ST42), and Taichong (LR3) on the feet are the most crucial.
Response: The Cun Kou is the great gathering point of pulses and is the pulsating artery of the Hand-Taiyin Lung meridian.
"Ran" is a particle indicating a response. "Hui" means gathering. The Hand-Taiyin is the meridian of the Lung. It is said that the Lung governs Qi, and the pulsations of the twelve meridians are all driven by Lung Qi. Therefore, it is said that the Lung faces all vessels, and the Qi gathers at the Cun Kou. The Cun Kou refers to the meaning in *Su Wen: Chapter on Distinguishing Meridians* that "the Qi-kou becomes Cun, to decide life and death," hence it is called Cun Kou. The Cun Kou is divided into three positions: Yuji (LU10) is the Cun position, the high bone at Taiyuan (LU9) is the Guan position, and Jingqu (LU8) is the Chi position. This is the pulsating artery of the Hand-Taiyin Lung meridian. When food enters the stomach, its clear Qi ascends to the Lung to coordinate with respiration and govern pulse dynamics. The intent of Yue Ren's question lies in exclusively taking the Cun Kou, a method revered by later generations as an unchangeable standard. Chapter 45 of *Nan Jing* mentions "Pulse meets at Taiyuan," which shares this same principle.
In one exhalation, the pulse moves three Cun; in one inhalation, the pulse moves three Cun. At the pause between breaths (Ding Xi), the pulse moves six Cun. In one day and night, there are thirteen thousand five hundred breaths, during which the pulse circulates fifty times around the body. Over the time it takes for water to drip one hundred marks (Ke), Ying Qi (Nutritive Qi) travels twenty-five times through the Yang aspects and twenty-five times through the Yin aspects, constituting one complete cycle. Thus, after fifty cycles, it reunites at the Hand-Taiyin Lung meridian. The Cun Kou is the beginning and end of the Qi of the five Zang and six Fu organs; therefore, the diagnostic method takes its standard from the Cun Kou.
This passage continues from the previous discussion, referring to a "Ping Ren" (healthy person), who does not suffer from disease and has regular breathing. *Ling Shu: Chapter on Fifty Circulations* records: Over the time of one hundred water marks, dividing day and night, in one exhalation the pulse beats twice, and Qi moves three Cun; in one inhalation the pulse also beats twice, and Qi moves three Cun. At the pause between breaths, Qi moves six Cun. In ten breaths, Qi moves six Chi; in two hundred and seventy breaths, Qi moves sixteen Zhang and two Chi, completing one circulation around the body, corresponding to two water marks; in two thousand seven hundred breaths, Qi completes ten circulations around the body, corresponding to twenty water marks; in thirteen thousand five hundred breaths, Qi completes fifty circulations around the body, corresponding to one hundred water marks, totaling eight hundred and ten Zhang. *Ying Wei Hui Hui Chapter* states: Humans derive Qi from grain. Grain enters the stomach and is transmitted to the Lung. Its clear portion becomes Ying Qi (Nutritive Qi), and its turbid portion becomes Wei Qi (Defensive Qi). Ying Qi circulates within the vessels, while Wei Qi circulates outside the vessels. Ying Qi circulates endlessly, meeting again after fifty cycles. Wei Qi and Ying Qi both travel twenty-five times through the Yang aspects and twenty-five times through the Yin aspects, forming one cycle. Thus, they also meet again at the Hand-Taiyin Lung meridian after fifty cycles. *Su Wen: Chapter on Normal Pulse Phenomena* states: In one exhalation the pulse beats twice, in one inhalation it beats twice. At the pause between breaths, the pulse beats five times, occasionally supplemented by a deep sigh (Tai Xi), which is defined as a healthy person. This pulse reflects Ying Qi. Ying Qi circulates through the meridians fifty times a day. Today at dawn, it starts at the Cun Kou of the Hand-Taiyin Lung meridian; tomorrow at dawn, it will meet again at the Cun Kou of the Hand-Taiyin Lung meridian. Since this is the beginning and end of the Qi of the five Zang and six Fu organs, the diagnostic method takes its standard from the Cun Kou.
Commentary: The pulse is the Qi within the blood. The term "Ying Qi" in the classics implies its operation within the vessels. Western medicine posits that after food enters the stomach and small intestine, micro-vessels absorb its essence. This fluid ascends to the jugular confluence, passes through the lungs, and enters the left atrium of the heart. (The heart is hollow internally, with rough, concave, or convex walls. A septum divides it into left and right atria; further horizontal partitions divide them into upper and lower sections. Fibrous strands connect these parts, allowing automatic opening and closing to respond to respiration.) The fluid transforms into red blood, which corresponds to the "clear portion becoming Ying Qi." Blood flows from the left atrium to the left ventricle, enters the main arterial vessel, runs along the spinal muscles, and circulates through the meridians fifty times a day and night, traversing eight hundred and ten Zhang of vascular pathways, responding to respiration. The "dripping water" refers to Ying Qi. As for Wei Qi, it implies protection on the exterior. The Qi and blood within the meridians exit from the ends of the vessels into the Qi Gates, entering the micro-vessels (referred to as Sun Luo in classics). Here, they combine with the fierce Qi of the Yangming meridian. (Food consists of five flavors; how can it be non-toxic? Western medicine calls this "carbon gas," referring to this phenomenon.) This mixture spreads throughout the skin and interstices, filling the skin, warming the flesh, and permeating the hair follicles. This corresponds to the "turbid portion becoming Wei Qi." Once the red blood in the main vessels enters the micro-vessels and combines with the fierce Qi of Yangming, its color gradually turns purple. Western medicine considers this toxic and calls it "carbon gas." Spreading throughout the body, these vessels merge and thicken, connecting to the tails of the venous vessels (referred to as Luo Mai in classics). Blood enters the veins, circulating internally to the Zang-Fu organs and externally to the meridians and arteries, moving in alternating directions. Those traveling outside the main meridians have Yin and Yang distinctions: one branch floats above the muscle layers, and another sinks between the muscle fibers. That is, Yang Luo circulates on the surface of the skin, and Yin Luo circulates beneath the skin, both moving alongside the main vessels. This aligns with the classic statement that Ying Qi moves within the vessels and Wei Qi moves outside. After circulating extensively inside and outside the veins, blood enters the main venous trunk, reaches the right atrium, falls into the right ventricle, and is delivered to the lungs. It exhales the fierce Qi and inhales vital Qi, transforming back into red blood, entering the left atrium. The mutual connection of Yin and Yang, like a circle without beginning or end, is what is meant here. However, Qi contains Blood, and Blood contains Qi; they cannot be separated for a moment. This is the natural principle of Yin and Yang rooting each other. The Qi and blood operating within the meridians, circulating fifty times day and night, move swiftly like the moon influencing water flowing through the earth. The Qi and blood exiting the Qi Gates, combining with the fierce Qi of Yangming, and spreading throughout the body, circulate once day and night, moving slowly like the sun following the celestial path around the earth. Thus, humans correspond to Heaven and Earth. The movement through Yin and Yang refers to the Qi and blood in the Yin and Yang Luo meridians accompanying the Wei Qi along the meridians. Regarding external pathogens attacking the body, heat injures Qi, and cold injures Blood; one should investigate the Wei Qi spread via the Sun Luo throughout the body. For latent Qi erupting internally, one should investigate the Wei Qi within the Luo meridians. Those floating outside the vessels can be treated with acupuncture to drain the Qi; those sinking inside the vessels require urgent attack to eliminate toxicity. When diagnosing pulses to examine disease, one should investigate the Ying Qi operating within the main vessels. Because blood entering the upper atrium, falling to the lower atrium, and passing through the main vessel involves opening and closing sounds corresponding to respiration, the pulse rate can be observed. Western medicine listens to sounds to diagnose heart diseases, adopting this same principle.