窃闻三阴三阳，有枢机焉。枢者，如门户之枢，乃阴阳开阖之转机也。《内经》枢机有
二∶一曰少阴为枢；一曰少阳为枢。阴之初生为少阴，少阴，稚阴也。手少阴属心，足少阴
属肾。心为人身君主之官，神明所从出。肾为阴阳互根之地，精气之本原。故少阴为转阳至
阴之机窍，阴之枢也。由少阴而太阴，由太阴而厥阴，经曰∶太阴为开，厥阴为阖。盖太阴
脾土，得此枢而散精以升于上；太阴肺金，得此枢而布精以降于下，能升能降，故谓之开。
由是厥阴心包络，得此枢而阴血以生；厥阴肝木，得此枢而阴血以藏，以生以藏，故谓之阖
。是太阴、厥阴之开阖，皆少阴之枢所默运者也。厥阴为阴之极，阴极则阳生，而阴转入于
阳，阳之初生为少阳，少阳，稚阳也。手少阳属三焦，足少阳属胆。三焦具真阳之火，其体
虚润，其气氤氲。（焦，热也。满腔中热气布 ，能通调水道也。按三焦从右肾生出，心
肾
阴至阳之机括，阳之枢也。由少阳而太阳，由太阳而阳明，经曰∶太阳为开，阳明为阖。盖
太阳膀胱，得此枢而水道通调；太阳小肠，得此枢而食物变化，通调变化，故谓之开。由是
阳明胃腑，得此枢而阳气含纳；阳明大肠，得此枢而阳气收藏，含纳收藏，故谓之阖。是太
阳、阳明之开阖，皆少阳之枢所默运者也。阳明为阳之极，阳极则阴生，而阳又转入于阴。
然则少阴、少阳，非阴阳出入开阖之枢机者哉？若其枢一有不利，则出入之机停；出入机停
，则开阖之机废。能开不能阖，则泄泻诸病生；能阖不能开，则噎膈、便闭诸病生。
病先天则从肾起，病后天则从脾胃起。脾胃病则土不生金而金败，金败则水衰，水衰则
木枯，木枯则火炽，火炽则水益涸，水涸则龙火起，龙火起而风火、雷火、燥火亦相继而起
，则一身无非火矣。夫此火之来，总由于枢之不利，火即阳气外越，而不能根据附于阴者也。
若寒以降之，则火益烈而元气亡矣。故欲其枢之利，非温润之、咸柔之不可。法当滋肾之阴
，纳肾之阳，盖肾为水火互根之脏，肾阴足而后水济火，肾阳固而后气归精也；法当养肝之
血，达胆之气，盖肝胆为东方震巽之木，木之阴液不可耗，木之生气尤不可伐也。知少阴、
少阳之为枢，而治法可悟矣。
我听说三阴三阳之中，存在着枢机。所谓“枢”，就像门户的转轴，是阴阳开合转换的关键环节。《内经》中提到的枢机有两处：一是说少阴为枢；二是说少阳为枢。
阴气初生时为少阴（Shao Yin，稚嫩的阴气），少阴属于稚阴。手少阴经归属于心，足少阴经归属于肾。心是人身体里君主之官，神明由此发出。肾是阴阳互相依存的根本之地，也是精气的本源。所以少阴是阳气转入阴气的机窍，也就是阴的枢机。
从少阴发展到太阴（Tai Yin），再从太阴发展到厥阴（Jue Yin），经文说：“太阴为开，厥阴为阖。”大概因为太阴脾土，得到这个枢机的作用而散布精气上升于上；太阴肺金，得到这个枢机的作用而布散精气下降于下，能够升能够降，所以称之为“开”。
由此到了厥阴心包络（Pericardium），得到这个枢机而生出阴血；厥阴肝木，得到这个枢机而贮藏阴血，能够生能够藏，所以称之为“阖”。因此，太阴和厥阴的开与阖，都是依靠少阴的枢机在暗中运作的。
厥阴是阴气的极点，阴气极盛则阳气产生，于是阴气转入转化为阳。阳气初生时为少阳（Shao Yang，稚嫩的阳气），少阳属于稚阳。手少阳经归属于三焦（San Jiao，上、中、下三焦的功能系统），足少阳经归属于胆（Gallbladder）。三焦具备真阳之火，其形体虚润，其气氤氲弥漫。（注：焦，意为热。满腔中的热气分布，能够通调水道。按：三焦从右肾生出，是心肾之间由阴至阳的关键机关，也就是阳的枢机。）
从少阳发展到太阳（Tai Yang），再从太阳发展到阳明（Yang Ming），经文说：“太阳为开，阳明为阖。”大概因为太阳膀胱（Urinary Bladder），得到这个枢机而水道通调；太阳小肠（Small Intestine），得到这个枢机而使食物发生变化，通调和变化，所以称之为“开”。
由此到了阳明胃腑（Stomach），得到这个枢机而含纳阳气；阳明大肠（Large Intestine），得到这个枢机而收藏阳气，含纳和收藏，所以称之为“阖”。因此，太阳和阳明的开与阖，都是依靠少阳的枢机在暗中运作的。
阳明是阳气的极点，阳气极盛则阴气产生，于是阳气又转入转化为阴。既然这样，难道少阴和少阳不是阴阳出入、开合转换的枢机吗？
如果这个枢机一旦不利，那么出入的机制就会停滞；出入机制停滞，那么开合的机制就会废弛。如果能开不能阖，就会产生泄泻等各种疾病；能阖不能开，就会产生噎膈（Yi Ge，吞咽困难）、便秘等各种疾病。
病发于先天则从肾（Kidney）开始，病发于后天则从脾胃（Spleen and Stomach）开始。脾胃生病则土不生金导致金败，金败则水衰，水衰则木枯，木枯则火炽，火炽则水更加枯竭，水枯竭则龙火（Long Huo，指肾中相火）兴起，龙火兴起则风火、雷火、燥火也相继而起，那么全身就没有不是火的了。
这种火的到来，总归是由于枢机不利，火即是阳气外越，而不能依附于阴。如果用寒凉药来降它，那么火会更加猛烈而元气灭亡。所以想要让枢机通畅，非用温润之法、咸柔之法不可。
治疗方法应当滋补肾阴，收纳肾阳，因为肾是水火互相依存的脏腑，肾阴充足之后才能以水济火，肾阳稳固之后气才能归于精。治疗方法还应当滋养肝血，疏达胆气，因为肝胆是东方震巽之木，木的阴液不可耗损，木的生气尤其不可伐害。明白了少阴和少阳作为枢机的道理，治疗的方法就可以领悟了。
I have heard that within the Three Yin and Three Yang meridians, there exists a "pivot" (Shu Ji). The term "pivot" is like the hinge of a door; it is the transitional mechanism for the opening and closing of Yin and Yang. The *Neijing* (Inner Canon) mentions two pivots: one states that Shaoyin is the pivot; the other states that Shaoyang is the pivot.
When Yin energy first arises, it is called Shaoyin (Lesser Yin), which is tender Yin. The Hand-Shaoyin meridian belongs to the Heart, and the Foot-Shaoyin meridian belongs to the Kidney. The Heart is the sovereign official of the human body, from which Shenming (Spirit/Mind) emerges. The Kidney is the place where Yin and Yang mutually root each other and the origin of Jingqi (Essence and Qi). Therefore, Shaoyin is the orifice through which Yang transforms into Yin, serving as the pivot of Yin.
From Shaoyin progresses to Taiyin (Greater Yin), and from Taiyin progresses to Jueyin (Terminal Yin). The classics state: "Taiyin is the Opening, Jueyin is the Closing." Generally speaking, the Spleen Earth of Taiyin, obtaining this pivot, scatters essence to ascend upwards; the Lung Metal of Taiyin, obtaining this pivot, distributes essence to descend downwards. Being able to ascend and descend, it is called "Opening."
Thereafter, the Pericardium of Jueyin, obtaining this pivot, generates Yin blood; the Liver Wood of Jueyin, obtaining this pivot, stores Yin blood. Being able to generate and store, it is called "Closing." Thus, the Opening and Closing of Taiyin and Jueyin are all silently operated by the pivot of Shaoyin.
Jueyin is the extreme of Yin. When Yin reaches its extreme, Yang is born, and Yin turns back into Yang. When Yang energy first arises, it is called Shaoyang (Lesser Yang), which is tender Yang. The Hand-Shaoyang meridian belongs to the Sanjiao (Triple Burner), and the Foot-Shaoyang meridian belongs to the Gallbladder. The Sanjiao possesses the fire of True Yang; its substance is void and moist, and its Qi is misty and pervasive. (Note: Jiao means heat. The heat Qi distributed throughout the cavity can unblock and regulate the water passages. According to theory, the Sanjiao originates from the right Kidney and serves as the mechanism for the transition from Yin to Yang between the Heart and Kidney, thus being the pivot of Yang.)
From Shaoyang progresses to Taiyang (Greater Yang), and from Taiyang progresses to Yangming (Bright Yang). The classics state: "Taiyang is the Opening, Yangming is the Closing." Generally speaking, the Urinary Bladder of Taiyang, obtaining this pivot, unblocks and regulates the water passages; the Small Intestine of Taiyang, obtaining this pivot, facilitates the transformation of food. Through regulation and transformation, it is called "Opening."
Thereafter, the Stomach of Yangming, obtaining this pivot, contains and accepts Yang Qi; the Large Intestine of Yangming, obtaining this pivot, collects and stores Yang Qi. Through containing/accepting and collecting/storing, it is called "Closing." Thus, the Opening and Closing of Taiyang and Yangming are all silently operated by the pivot of Shaoyang.
Yangming is the extreme of Yang. When Yang reaches its extreme, Yin is born, and Yang turns back into Yin. In this case, are not Shaoyin and Shaoyang the pivots of the entry and exit, opening and closing of Yin and Yang?
If this pivot becomes obstructed, the mechanism of entry and exit will stagnate; if the mechanism of entry and exit stagnates, the mechanism of opening and closing will become dysfunctional. If one can open but not close, diseases such as diarrhea will arise; if one can close but not open, diseases such as dysphagia (Yige) and constipation will arise.
Diseases originating from congenital factors begin in the Kidney, while diseases originating from acquired factors begin in the Spleen and Stomach. When the Spleen and Stomach are diseased, Earth fails to generate Metal, leading to the failure of Metal; when Metal fails, Water declines; when Water declines, Wood withers; when Wood withers, Fire blazes; when Fire blazes, Water dries up further; when Water dries up, Dragon Fire (Ministerial Fire arising from Kidney deficiency) rises; once Dragon Fire rises, Wind Fire, Thunder Fire, and Dryness Fire arise in succession, resulting in the entire body being dominated by Fire.
The arrival of this Fire is fundamentally due to the dysfunction of the pivot; the Fire represents Yang Qi escaping outward and failing to adhere to Yin. If one uses Cold-natured herbs to suppress it, the Fire will become even more fierce, and the Yuan Qi (Original Qi) will perish. Therefore, to ensure the smooth functioning of the pivot, it is imperative to use Warming-Moistening methods and Saline-Softening methods.
The treatment method should nourish Kidney Yin and gather Kidney Yang, because the Kidney is the zang organ where Water and Fire mutually root. Once Kidney Yin is sufficient, Water can control Fire; once Kidney Yang is solid, Qi can return to Essence. The treatment method should also nourish Liver Blood and diffuse Gallbladder Qi, because the Liver and Gallbladder belong to the Wood of East Zhen-Xun. The Yin fluid of Wood must not be depleted, and the Sheng Qi (Vitalizing Qi) of Wood must especially not be damaged. Understanding that Shaoyin and Shaoyang serve as pivots allows one to comprehend the therapeutic methods.