沉则轻取不应，重按乃得。凡细小实伏牢弱，皆属沉类。不似实脉之举指逼逼，伏脉之隐于筋骨也。（语
出张璐。又
濒湖体状诗曰∶水行润下脉来沉，
筋骨之间软滑匀；女子寸兮男子尺，四时号此为和平。相类诗曰∶沉帮筋骨自调匀，伏则推筋着骨寻；沉细如
绵真弱脉，弦长实大是牢形。）沉为痰寒不振，水气内伏，停饮不化，宿食不消，气逆不通，洞泄不
闭，故见内沉。若使沉而兼细，则为少气；沉而兼迟，则为痼冷；沉而兼滑，则为宿食；沉而兼伏，则为霍乱
绞痛；沉而兼数，则为内热；沉弦而紧，则为心腹疼痛。然总不越有力无力，以为辨别。盖沉实有力，宜消宜
攻；沉虚无力，宜温宜补。（然亦有有力宜温，无力宜攻，另有义详于后，当细互参。）若使沉紧而数，又兼
头痛发热恶寒，虽曰脉沉，仍属寒蔽，当作表治。岂可概认为里，而不用以升发乎。（张璐曰∶脉显阴象而沉
者，则按久愈微。若阳气郁伏，不能浮应卫气于外，脉反伏匿而沉者，则按久不衰。阴阳寒热之机，在乎纤
微之辨。伤寒以尺寸俱沉，为少阴受病。故于沉脉之中，辨别阴阳为第一关捩。林之翰曰∶沉脉须知主表。如
寒闭腠理，卫气不通，经气涩滞，脉不见浮而沉；气郁脉闭；下手便见，而脉亦沉；真阴久虚，真阳衰惫，
外邪乘虚直入，而脉亦沉；是沉仍属表症。）
沉脉的特征是轻取（轻按）感觉不到，重按（深按）才能触及。凡是细小、实、伏、牢、弱等脉象，都属于沉类脉。它们不像实脉那样举指时搏动强劲有力，也不像伏脉那样隐没在筋骨之间。（这段话出自张璐。另外，《濒湖脉学》的体状诗说道：水行润下，脉来深沉，在筋骨之间柔软滑利且均匀；女子在寸部、男子在尺部出现这种脉象，四季中称为平和之脉。相类诗说道：沉脉在筋骨间自然调匀，伏脉则需要推筋着骨去寻找；沉细如绵的是真弱脉，弦长实大的是牢脉的形状。）沉脉主痰饮、寒邪导致阳气不振，水气内伏，停饮不化，宿食不消，气逆不通，洞泄不禁，所以见到内部病变呈现沉脉。如果沉脉兼见细脉，则是少气；沉脉兼见迟脉，则是痼冷；沉脉兼见滑脉，则是宿食；沉脉兼见伏脉，则是霍乱绞痛；沉脉兼见数脉，则是内热；沉弦而紧，则是心腹疼痛。然而总归不离有力无力，以此作为辨别依据。大概沉实有力，适宜消导攻下；沉虚无力，适宜温补。（然而也有有力宜温，无力宜攻的情况，另有含义详见后文，应当仔细互参。）如果沉紧而数，又兼见头痛、发热、恶寒，虽然说是脉沉，仍属于寒邪闭阻，应当当作表证治疗。怎么能一概认为是里证，而不使用升发之法呢？（张璐说：脉象显现阴象而沉的，则久按愈微弱。如果是阳气郁伏，不能浮应于卫气于外，脉反而伏匿而沉的，则久按不衰。阴阳寒热的机理，在于细微的辨别。伤寒病以尺寸俱沉，为少阴经受病。所以在沉脉之中，辨别阴阳是第一关键。林之翰说：沉脉须知主表。如寒邪闭阻腠理，卫气不通，经气涩滞，脉不见浮而沉；气郁脉闭；下手便见，而脉亦沉；真阴久虚，真阳衰惫，外邪乘虚直入，而脉亦沉；这些情况沉脉仍属于表症。）
The Chen (Deep) pulse is not felt with light pressure but is obtained only with heavy pressure. All pulses such as Xi (Fine), Shi (Full), Fu (Hidden), Lao (Taut), and Ruo (Weak) belong to the category of Deep pulses. They do not resemble the Shi (Full) pulse, which feels vigorous under light lifting of the fingers, nor the Fu (Hidden) pulse, which is concealed within the sinews and bones. (This passage is from Zhang Lu. Additionally, the *Binhu Tizhuang Shi* [Poem on Pulse Characteristics by Li Shizhen] states: "Water flows downward; the pulse comes deep, soft, smooth, and even between sinews and bones; in women at the Cun position and in men at the Chi position, it is called 'Peaceful' across the four seasons." The *Xianglei Shi* [Poem on Similar Pulses] states: "The Deep pulse is naturally balanced between sinews and bones; the Hidden pulse requires pushing the sinew to reach the bone; Deep and fine like cotton is the true Weak pulse; Taut, long, full, and large is the form of the Lao pulse.") The Deep pulse indicates phlegm-fluids, cold pathogen causing failure of Yang Qi to rise, internal retention of water-qi, untransformed retained fluids, undigested food stagnation, rebellious Qi obstruction, and uncontrollable diarrhea; thus, internal conditions manifest as a Deep pulse. If the Deep pulse is accompanied by Fine, it indicates Shortness of Qi; if accompanied by Slow, it indicates Chronic Cold; if accompanied by Slippery, it indicates Undigested Food Stagnation; if accompanied by Hidden, it indicates Cholera-like colic pain; if accompanied by Rapid, it indicates Internal Heat; if Deep, Wiry, and Tight, it indicates Heart and Abdominal Pain. However, differentiation ultimately relies on whether the pulse is Forceful or Feeble. Generally, a Deep and Full/Forceful pulse is suitable for resolving stagnation and purging; a Deep and Deficient/Feeble pulse is suitable for warming and tonifying. (However, there are cases where a Forceful pulse requires warming, and a Feeble pulse requires purging; these have separate meanings detailed later and should be cross-referenced carefully.) If the pulse is Deep, Tight, and Rapid, accompanied by Headache, Fever, and Aversion to Cold, although the pulse is Deep, it still belongs to Cold Obstruction and should be treated as a Exterior Syndrome. How can it be generally considered an Interior Syndrome without using ascending and dispersing methods? (Zhang Lu said: When the pulse manifests Yin characteristics and is Deep, prolonged pressing makes it weaker. If Yang Qi is depressed and hidden, unable to float to respond to Wei Qi on the exterior, the pulse instead hides and becomes Deep, prolonged pressing does not diminish it. The mechanism of Yin/Yang and Cold/Heat lies in subtle distinctions. In Shanghan Disease, Deep pulses at both Cun and Chi positions indicate Shaoyin Meridian involvement. Therefore, distinguishing Yin and Yang among Deep pulses is the first critical step. Lin Zhihan said: One must understand that Deep pulses can indicate Exterior conditions. For example, when Cold closes the Couli (pores), blocking Wei Qi flow and causing sluggish Jing Qi, the pulse does not appear Floating but Deep; when Qi depression blocks the pulse, it appears Deep immediately upon palpation; when True Yin has been deficient for a long time and True Yang is exhausted, external pathogens enter directly due to deficiency, the pulse also becomes Deep; in these cases, the Deep pulse still belongs to Exterior Syndromes.)