九细者。阴也。指下寻之。细细似线。来往极微曰细。主胫酸髓冷乏力泄精。
九细者。阴也。云岐子取象于巽。主秋金有余。夫巽者风也。言人之精血
衰冷。如秋风之微弱萧瑟也。气主 之。血主濡之。气血盛则能变化精
微。内渗骨空。以实其骨髓。外荣肌内。以淖泽毛发。今指下寻之。脉道细
细似线。且来往极微。是从弦上减至极细而微矣。仲景曰。弦则为减。以
曰减则为寒。今减之又减。以至极细而微。则为肾水虚冷可知矣。所以
精道不固。则内无以实骨空。而胫寒髓冷。乏力泄精之证作矣。
按脉经云。细脉小大于微。常有但细耳。
乏力无精胫里酸。形容憔悴发毛干。如逢冬季经霜月。不疗其 必自痊。
血盛则脉盛。血衰则脉衰。上文言脉道细细似线。来往极微则脉道衰
矣。足胫属肾。胫酸属虚。皆由无精以实骨空。以至胫酸而乏力也。血不
足则不能华色。而形容憔悴。精不足则不能淖泽肌肤。发毛干枯。然春
夏为阳。秋冬为阴。春夏脉当浮大。秋冬脉当沉细。若秋冬而见此细脉。
则为顺四时。其病当不治自愈。若春夏见此沉细之脉。是于长养之时。
而见凋残之气。则为反四时矣。安能保其无大咎也。
按脉经云。寸口脉细。发热吸吐。宜服黄芩龙胆汤。吐不止。宜服橘皮桔
梗汤。灸中府。又云。关脉细。脾胃虚腹满。宜服平胃茱萸蜀椒汤。白薇丸。
针灸三管。
又按三部九候论云。尺脉细而急者。筋挛痹不能行。又云。尺脉细微。溏
泄。下冷利。
细脉，属于阴脉。在指下寻按之时，脉形细细如同丝线，往来搏动极其微弱，这称为细脉。它主要主司小腿酸痛、骨髓寒冷、乏力以及遗精等症状。
细脉属阴。云岐子将其取象于八卦中的巽卦。它主秋金之气有余。巽代表风，这里是用来说明人体的精血衰败寒冷，就像秋风一样微弱萧瑟。气具有推动的作用，血具有濡养的作用。气血旺盛时，能够化生精微物质，向内渗透骨空以充实骨髓，向外荣润肌肉以滋润毛发。如今在指下寻按时，脉道细细似线，且往来极其微弱，这是从弦脉的基础上减去至极细而微的状态。张仲景说：“弦则说明正气减损”，既然说是减损，那就是寒证。现在又是减损再减损，以至于极细而微，这就可知是肾水虚冷所致。所以精关不固，内部无法充实骨空，导致小腿寒冷、骨髓寒冷，乏力泄精的病症就发作了。
据《脉经》记载：细脉比微脉大，但小于小脉，始终只是细而已。
出现乏力、无精、小腿里酸痛，形容憔悴、毛发干枯。如果恰逢冬季经霜之月（秋冬季节），即使不治疗也必然会自愈。
血液旺盛则脉象盛大，血液衰少则脉象衰微。上文提到脉道细细似线，往来极其微弱，说明脉道已经衰微。足胫部归属于肾，小腿酸痛属于虚证，这都是因为没有精气来充实骨空，从而导致小腿酸痛和乏力。血液不足就不能荣华面色，导致面容憔悴；精气不足就不能滋润肌肤，导致毛发干枯。然而春夏属阳，秋冬属阴。春夏时节脉象应当浮大，秋冬时节脉象应当沉细。如果在秋冬季节见到这种细脉，就是顺应四时变化，其病应当不治自愈。如果在春夏季节见到这种沉细的脉象，这是在生长养育的时节，却见到了凋残的气象，这就是违背四时变化了，怎么能保证没有大的灾祸呢？
据《脉经》记载：寸口脉细，伴有发热、呕吐，适宜服用黄芩龙胆汤。如果呕吐不止，适宜服用橘皮桔梗汤。并灸中府穴。又记载：关脉细，为脾胃虚弱、腹部胀满，适宜服用平胃茱萸蜀椒汤和白薇丸。针灸三管穴。
又据《三部九候论》记载：尺脉细而急迫的，会出现筋脉拘挛、痹痛不能行走的症状。又记载：尺脉细微，出现溏泄、下部寒冷利下的症状。
The Fine Pulse (Xi Mai, 细脉) is a Yin pulse. When searched for under the fingers, it appears thin and thread-like, with extremely faint incoming and outgoing movements; this is defined as the Fine Pulse. It primarily indicates symptoms such as soreness in the shins, coldness of the marrow, fatigue, and seminal emission.
The Fine Pulse belongs to Yin. Yun Qizi (云岐子) associated its image with the Xun trigram (巽). It indicates an excess of Autumn Metal Qi. Xun represents Wind; here, it describes the decline and coldness of the body's essence and blood, akin to the weak and desolate autumn wind. Qi acts as the mover, while Blood acts as the nourisher. When Qi and Blood are abundant, they can transform into subtle essences, penetrating inward to fill the bone cavities and enrich the bone marrow, and radiating outward to nourish the muscles and moisten the hair and skin. Currently, when searching under the fingers, the pulse channel is thin like a thread, with extremely faint movements. This represents a reduction from the Wiry Pulse (Xian Mai, 弦脉) down to an extremely fine and faint state. Zhang Zhongjing stated: "Wiry indicates deficiency/reduction." Since it is described as reduced, it signifies Cold. Now, being reduced again to the point of extreme fineness and faintness, it is evident that there is a deficiency and coldness of Kidney Water. Consequently, the essence pathway becomes insecure, failing to internally fill the bone cavities, leading to cold shins, cold marrow, fatigue, and seminal emission.
According to the *Mai Jing* (Pulse Classic): The Fine Pulse is larger than the Micro Pulse (Wei Mai, 微脉) but smaller than the Small Pulse (Xiao Mai, 小脉); it is consistently merely fine.
Fatigue, lack of essence, and soreness within the shins; emaciated appearance and dry hair. If encountered during the frosty months of winter, even without treatment, it will likely heal spontaneously.
When Blood is abundant, the pulse is vigorous; when Blood is deficient, the pulse is weak. As mentioned above, a pulse channel that is thin like a thread with extremely faint movements indicates a weakening of the pulse channel. The lower legs belong to the Kidney; shin soreness indicates deficiency. All these arise from a lack of essence to fill the bone cavities, resulting in shin soreness and fatigue. Insufficient Blood cannot manifest luster in the complexion, leading to an emaciated appearance; insufficient Essence cannot moisten the skin and flesh, leading to dry and brittle hair. However, Spring and Summer belong to Yang, while Autumn and Winter belong to Yin. In Spring and Summer, the pulse should be Floating and Large (Fu Da, 浮大); in Autumn and Winter, the pulse should be Sinking and Fine (Chen Xi, 沉细). If this Fine Pulse is seen in Autumn and Winter, it conforms to the Four Seasons, and the illness should resolve spontaneously without treatment. If this Sinking and Fine Pulse is seen in Spring and Summer, it represents a withering Qi during a time of growth and nurturing, which contradicts the Four Seasons. How can one ensure there will be no major disaster?
According to the *Mai Jing*: If the Cun Kou (Inch Position) pulse is Fine, accompanied by fever and vomiting, Huang Qin Long Dan Tang (Scutellaria and Gentian Decoction) is suitable. If vomiting persists, Ju Pi Jie Geng Tang (Tangerine Peel and Platycodon Decoction) is suitable. Moxibustion should be applied to Zhong Fu (LU-1, Middle Palace). It also states: If the Guan (Bar Position) pulse is Fine, indicating Spleen and Stomach deficiency with abdominal fullness, Ping Wei Zhu Yu Shu Jiao Tang (Stomach-Pingulating, Cornus and Sichuan Pepper Decoction) and Bai Wei Wan (Anemone Pill) are suitable. Acupuncture or moxibustion should be applied to San Guan (Three Tubes) points.
Furthermore, according to the *San Bu Jiu Hou Lun* (Discourse on Three Regions and Nine Palpations): If the Chi (Cubit Position) pulse is Fine and rapid, it indicates tendon spasms, bi-syndrome (painful obstruction), and inability to walk. It also states: If the Chi pulse is Fine and Micro, it indicates loose stools and cold diarrhea in the lower jiao.