细脉，小于微而常有，细直而软，若丝线之应指（《脉经》）。《素问》谓之小。王启玄言如莠蓬，状其柔细也。《脉
诀》言∶往来极微，是微反大于细矣，与《经》指背。
〔体状诗〕细来累累细如丝，应指沉沉无绝期。春夏少年俱不利，秋冬老弱却相宜。
〔相类诗〕见微、濡。
〔主病诗〕细脉萦萦血气衰，诸虚劳损七情乖。若非湿气侵腰肾，即是伤精汗泄来。寸细应知呕吐频，入关腹胀胃
虚形。尺逢定是丹田冷，泄痢遗精号脱阴。《脉经》曰∶细为血少气衰。有此证则顺，否则逆。故吐衄得沉细者生。忧
劳过度者，脉亦细。
伏脉，重按着骨，指下裁动（《脉经》）。脉行筋下（《刊误》）。《脉诀》言∶寻之似有，定息全无，殊为舛谬。
〔体状诗〕伏脉推筋着骨寻，指间裁动隐然深。伤寒欲汗阳将解，厥逆脐疼证属阴。
〔相类诗〕见沉脉。
〔主病诗〕伏为霍乱吐频频，腹痛多缘宿食停。蓄饮老痰成积聚，散寒温里莫因循。食郁胸中双寸伏，欲吐不吐常
兀兀。当关腹痛困沉沉，关后疝疼还破腹。伤寒，一手脉伏曰单伏，两手脉伏曰双伏，不可以阳证见阴为诊。乃火邪内
郁，不得发越，阳极似阴，故脉伏，必有大汗而解。正如久旱将雨，六合阴晦，雨后庶物皆苏之义。又有夹阴伤寒，先
有伏阴在内，外复感寒，阴盛阳衰，四脉厥逆，六脉沉伏，须投姜附及灸关元，脉乃复出也。若太溪、冲阳皆无脉者，
必死。《脉诀》言∶徐徐发汗。洁古以附子细辛麻黄汤主之，皆非也。刘元宾曰∶伏脉不可发汗。
细脉，比微脉更小但持续存在，脉形细直而柔软，指下感觉如同丝线一般（《脉经》）。《素问》中称之为“小”。王启玄形容其像莠蓬草一样，描述其柔和纤细的形态。《脉诀》中说：“往来极其微弱”，这导致微脉反而看起来比细脉大，这与《脉经》的原意背道而驰。
〔体状诗〕细脉来去连绵不断，细如丝线，按之沉稳且无断绝之时。春夏季节及年轻人得此脉均不利，秋冬季节及年老体弱者得此脉却相适宜。
〔相类诗〕参见微脉、濡脉。
〔主病诗〕细脉萦萦不绝，主血气衰败，各种虚损劳伤及七情失调。如果不是湿气侵袭腰肾，就是因耗伤精液或汗出过多所致。寸部出现细脉，应知呕吐频繁；关部出现细脉，主腹胀且胃气虚弱；尺部出现细脉，定是丹田寒冷，泄泻、痢疾、遗精等症状被称为脱阴证。《脉经》说：“细脉主血少气衰。”有这些症状则脉证相符为顺，否则为逆。所以吐血、衄血患者若出现沉细脉则预后良好。忧思劳累过度的人，脉象也会变细。
伏脉，重按至骨，指下才能感觉到脉搏跳动（《脉经》）。脉行于筋下（《刊误》）。《脉诀》中说：“轻寻似有，定息全无”，这是非常错误的。
〔体状诗〕伏脉需推筋按骨方可寻得，指下感觉隐然深藏。伤寒欲出汗而阳气将解时可见，厥逆脐痛属于阴证。
〔相类诗〕参见沉脉。
〔主病诗〕伏脉主霍乱，呕吐频繁；腹痛多因宿食停滞。水饮蓄积、老痰形成积聚，应散寒温里，不可拖延。食积阻滞胸中，双寸脉伏，想吐又吐不出，常感心中烦闷不适。关部腹痛沉重困倦，关后疝气疼痛甚至破腹。伤寒病中，一手脉伏称为单伏，两手脉伏称为双伏，不能因为阳证见到阴脉就诊断为阴证。这是因为火邪内郁，不得发散，阳极似阴，所以脉伏，必然要通过大汗而解。正如久旱将雨时，天地昏暗，雨后万物复苏的道理一样。又有夹阴伤寒，先有伏阴在内，外感寒邪，阴盛阳衰，四肢厥逆，六脉沉伏，必须投用姜附类药物并灸关元穴，脉象才会复出。如果太溪穴、冲阳穴都摸不到脉搏，必死无疑。《脉诀》说：“徐徐发汗。”洁古先生用附子细辛麻黄汤主治，都不正确。刘元宾说：“伏脉不可发汗。”
The Xi (Fine) pulse is smaller than the Wei (Minute) pulse but persists; it is straight and soft, feeling like a silk thread under the fingers (*Mai Jing*). The *Su Wen* refers to it as "Xiao" (Small). Wang Qixuan described it as resembling the downy seeds of a weed, characterizing its softness and fineness. The *Mai Jue* states: "Coming and going extremely minute," which implies that the Wei pulse appears larger than the Xi pulse, contradicting the meaning in the *Jing*.
[Body Form Poem] The Xi pulse comes and goes continuously, fine as silk, pressing steadily without interruption. It is unfavorable for spring and summer, and for the young; however, it is suitable for autumn and winter, and for the elderly or weak.
[Similarity Poem] See Wei (Minute) and Ru (Floating Soft) pulses.
[Main Disease Poem] The lingering Xi pulse indicates depletion of blood and Qi, various deficiency consumptions, and emotional disharmony. If not caused by dampness invading the waist and kidneys, it results from essence injury or excessive sweating. A Xi pulse at the Cun (Inch) position indicates frequent vomiting; at the Guan (Bar) position, abdominal distension due to stomach deficiency; at the Chi (Cubit) position, coldness in the Dantian, with symptoms such as diarrhea, dysentery, and seminal emission classified as Tuoyin (Collapse of Yin). The *Mai Jing* states: "Xi indicates insufficient blood and declining Qi." If these symptoms are present, the pulse matches the condition (Shun); otherwise, it is adverse. Therefore, patients with hematemesis or epistaxis who present with a Chen-Xi (Deep-Fine) pulse will survive. Those suffering from excessive worry and labor also have a Xi pulse.
The Fu (Hidden) pulse requires heavy pressure until the bone to feel the movement under the fingers (*Mai Jing*). The pulse travels beneath the tendons (*Kan Wu*). The *Mai Jue* states: "Searching lightly seems to have it, holding breath makes it disappear completely," which is highly erroneous.
[Body Form Poem] The Fu pulse must be sought by pushing aside tendons to press against the bone; the movement feels hidden and deep. In Shanghan (Cold Damage), when sweat is about to occur and Yang is resolving, or in Jueni (Cold Reversal) with umbilical pain, the syndrome belongs to Yin.
[Similarity Poem] See Chen (Deep) pulse.
[Main Disease Poem] The Fu pulse indicates Huoluan (Cholera-like disorder) with frequent vomiting; abdominal pain often stems from retained food. Accumulated fluids and old phlegm form masses; one must dispel cold and warm the interior without delay. Food stagnation in the chest causes both Cun positions to be Fu, with an urge to vomit that cannot be expelled, leading to constant discomfort. Abdominal pain at the Guan position feels heavy and sluggish; hernia pain behind the Guan may rupture the abdomen. In Shanghan, a Fu pulse in one hand is called Danfu (Single Hidden); in both hands, Shuangfu (Double Hidden). One should not diagnose Yin syndrome simply because Yin pulses appear in Yang syndromes. This occurs because Fire pathogen is internally constrained and cannot vent out; extreme Yang resembles Yin, so the pulse is Fu, and resolution must come through profuse sweating. This is like the sky darkening before rain after a long drought, after which all things revive upon rain. There is also Jiyin Shanghan (Cold Damage with Clamped Yin), where latent Yin exists internally, compounded by external cold invasion, leading to Yin excess and Yang decline, four extremities cold reversal, and six pulses sinking and hidden. One must administer Ginger and Aconite formulas and moxa Guanyuan (CV4) for the pulse to reappear. If Taixi (KI3) and Chongyang (ST42) pulses are absent, death is certain. The *Mai Jue* suggests "slowly inducing sweat." Jiegu used Fuzi Xixin Mahuang Tang (Aconite Twig, Asarum, and Ephedra Decoction) as the main treatment, both of which are incorrect. Liu Yuanbin stated: "The Fu pulse should not be treated with sweating methods."