Zusanli (ST36), the He (Earth) point of the Stomach Meridian of Foot-Yangming, is not only the “Longevity Point” recorded in traditional Chinese medicine (TCM) literature but also one of the most clearly understood acupoints in modern acupuncture research regarding its mechanism of action.

足三里（ST36），作為足陽明胃經之合（土）穴，不僅是傳統中醫文獻中記載的「長壽穴」，更是現代針灸研究中作用機制最為清晰的穴位之一。

This article aims to combine the localization principles of classical acupuncture with contemporary evidence from anatomy and neuroimmunology, deeply analyzing the structural basis of ST36, and exploring its multi-level mechanisms in regulating the digestive system and systemic anti-inflammation, while comprehensively summarizing its broad clinical applications across ancient and modern times.

本文旨在結合古典針灸學的定位原則與當代解剖學、神經免疫學的實證，深入剖析 ST36 的結構基礎，並探討其在消化系統、全身性抗炎調控中的多層次作用機制，同時全面總結其跨越古今的廣泛臨床應用。

The name Zusanli first appears in the Huangdi Neijing (Yellow Emperor’s Inner Canon), referring to its precise relative location and implying its potent tonic function:

足三里之名，最早可見於《黃帝內經》，指涉其精確的相對位置，並暗示其強大的補益功能：

“The so-called Sanli is three cun below the knee.”——Suwen, Zhenjie Pian (Plain Questions, Chapter on Acupuncture Explanation) [1]
「所謂三里者，下膝三寸也。」——《素問‧鍼解篇》 [1]

ST36 belongs to the Stomach Meridian of Foot-Yangming and is the He (Earth) point of this meridian.

ST36 歸屬於足陽明胃經，是該經脈的合（土）穴。

Classical TCM summarizes its core functions as: regulating the Spleen and Stomach, harmonizing the intestines and resolving stagnation, clearing heat and transforming dampness, descending rebellious Qi and regulating its flow, and supporting the vital essence and consolidating the fundamental health (Fuzheng Peiyuan).

古典中醫界將其核心功效歸納為：調理脾胃，和腸消滯，清熱化濕，降逆利氣，扶正培元。

Regarding localization, the Zhenjiu Zisheng Jing (Canon of Acupuncture and Moxibustion for Longevity) emphasizes that the point is located three cun below Dubi (lateral knee eye), and cautions against taking the measurement directly from the knee head, warning that doing so would be “too high” [2].

在定位上，《針灸資生經》強調其位於犢鼻（外膝眼）之下三寸，並指出不能從膝頭直接向下取穴，否則「恐失之太高矣」 [2]。

Modern clinical practice, combined with other documents (such as the Xunjing Kaoxue Bian complementing the horizontal position), has established the precise needling standard as three cun below Dubi, one finger-breadth lateral to the anterior crest of the tibia.

現代臨床則結合了其他文獻（如《循經考穴編》對橫向定位的補充），確立了犢鼻下三寸，脛骨前緣外側一橫指處的精準取穴標準。

The broad biological effects of ST36 stem from its rich neurovascular structure, which provides an efficient pathway for somatosensory signals.

足三里具備廣泛的生物學效應，是基於其所在的豐富神經血管結構，為體感訊號的傳入提供了高效通路。

ST36 is located on the anterolateral aspect of the lower leg, with the deep muscle tissue penetrated during needling including the Tibialis Anterior Muscle and the Extensor Digitorum Longus lateral to it [3].

ST36 位於小腿前外側，針刺時通過的肌肉組織包括深層的脛骨前肌 (Tibialis Anterior Muscle) 和其外側的趾長伸肌 (Extensor Digitorum Longus)。

Stimulation of these muscle groups forms the structural basis for achieving the characteristic “De Qi” sensation and myofascial mechanical pull in acupuncture [3].

這些肌群的刺激是針灸產生「得氣」感和牽引作用的結構基礎 [3]。

The point is intimately associated with the Deep Peroneal Nerve.

它與腓深神經 (Deep Peroneal Nerve) 密切相關。

The Deep Peroneal Nerve, a distal branch of the Common Peroneal (Fibular) Nerve derived from the Sciatic Nerve, acts as a carrier for somatosensory input, transmitting signals to the spinal cord and brainstem, making it a core afferent pathway by which ST36 can influence visceral function via somato-visceral reflexes [3].

腓深神經為坐骨神經經腓總（腓骨）神經分出的遠端分支，作為體感輸入的載體，可將刺激訊號傳遞至脊髓與腦幹，成為 ST36 透過體感－內臟反射影響內臟功能的重要傳入途徑 [3]。

The Anterior Tibial Artery and Vein run deep to the acupoint.

穴位深層有脛前動、靜脈 (Anterior Tibial Artery and Vein) 通過。

Modern research confirms that stimulating ST36 is not merely a local effect but generates systemic regulation through a multi-level neuro-immune circuit extending from the periphery to the central nervous system (CNS) [4]:

現代研究證實，刺激 ST36 並非簡單的局部作用，而是通過一個從體表到中樞的多級神經免疫迴路，產生全身性的調節效應 [4]：

Stimulation of ST36 activates sensory fibers in the Deep Peroneal/Sciatic Nerve, with signals ascending to the CNS.

刺激 ST36 啟動腓深神經/坐骨神經中的感覺纖維，訊號經由脊髓上行，投射至中樞。

Key central nuclei involved in this signal integration include:

中樞整合的關鍵核團包括：

Signals integrated in the CNS activate the body’s intrinsic Cholinergic Anti-inflammatory Pathway.

中樞整合後的訊號活化了人體內建的膽鹼能抗炎通路 (Cholinergic Anti-inflammatory Pathway)。

The activated signal is efferently transmitted via the Vagus Nerve to abdominal organs, particularly the Spleen.

訊號經由活化的迷走神經 (Vagus Nerve) 傳出，到達腹腔器官，尤其是脾臟 (Spleen)。

Vagal nerve endings release acetylcholine, which acts on immune cells (such as macrophages), inhibiting the NF-κB pathway.

迷走神經末梢釋放乙醯膽鹼，作用於免疫細胞（如巨噬細胞），抑制 NF-κB 通路。

This results in reduced release of pro-inflammatory cytokines such as TNF-α and IL-1β, achieving a systemic anti-inflammatory effect [5].

從而減少 TNF-α、IL-1β 等促炎細胞因子的釋放，實現全身性的抗炎效果 [5]。

The broad clinical application of ST36 spans from traditional harmonization of Qi and Blood to modern regulation of the endocrine and immune systems.

ST36 的應用範圍極廣，涵蓋了從傳統氣血調和到現代內分泌與免疫系統的調節。

Classical texts record the ability of ST36 to treat multisystem disorders, particularly excelling in addressing Spleen-Stomach deficiency and abnormal ascent/descent of Qi, including:

古典文獻記錄了 ST36 在多系統疾病中的調治能力，尤其擅長處理脾胃虛弱和氣機升降失常，主要包括：

Based on the modern understanding of its neuroimmune regulatory effects, ST36 is also widely used to address modern medical challenges:

基於現代科學對其神經免疫調控作用的理解，ST36 亦廣泛應用於現代醫學難題：

In clinical practice, ST36 is often used as a core acupoint, synergizing with others to achieve more precise therapeutic goals:

在臨床實踐中，ST36 常作為核心穴位，與其他穴位協同，實現更精準的治療目的：

The mechanism of Zusanli (ST36) has evolved from ancient empirical principles into a modern scientific system based on precise neuroanatomy and biochemical pathways.

足三里（ST36）的作用機制，已經從古代的經驗法則，演變為一套基於精確神經解剖和生物化學通路的現代科學體系。

As a cutaneous interface that activates the CNS via the peripheral nervous system to regulate the endocrine and immune systems, it provides an effective non-pharmacological intervention for various complex diseases.

它作為一個通過周邊神經系統啟動中樞神經系統，進而調控內分泌與免疫系統的體表介面，為多種複雜疾病提供了有效的非藥物干預手段。

The broad clinical application spectrum of ST36 serves as the best evidence for its multi-level biological efficacy.

ST36 廣泛的臨床應用譜系，正是其多層次生物學效應的最佳佐證。

1. Huangdi Neijing Suwen (Yellow Emperor’s Inner Canon, Plain Questions). Zhenjie Pian. Ancient Chinese medical classic. (Classical discussion on ST36 localization)
   《黃帝內經‧素問》。鍼解篇。中國古代醫學典籍。 (經典論述足三里定位)
2. Zhenjiu Zisheng Jing (Canon of Acupuncture and Moxibustion for Longevity). By Wang Zhizhong, Yuan Dynasty. Ancient Chinese monograph on acupuncture. (Discusses ST36 needling methods and application)
   《針灸資生經》。元・王執中撰。中國古代針灸學專著。 (論述足三里取穴手法及應用)
3. Yan, Zhenguo. Xue Wei Jie Pou Xue (Acupoint Anatomy). Shanghai Scientific and Technical Publishers, 2004. (Provides detailed anatomical information on the deep structure of ST36)
   嚴振國。《穴位解剖學》。上海科學技術出版社，2004。 (提供足三里穴位深部結構的解剖學詳情)
4. Li, N., Guo, Y., Gong, Y., et al. The Anti-Inflammatory Actions and Mechanisms of Acupuncture from Acupoint to Target Organs via Neuro-Immune Regulation. J Inflamm Res. 22 Dec 2021; 14: 7191–7224. (Review on the neuroimmune mechanism of acupuncture anti-inflammation)
   Li, N., Guo, Y., Gong, Y., et al. The Anti-Inflammatory Actions and Mechanisms of Acupuncture from Acupoint to Target Organs via Neuro-Immune Regulation. J Inflamm Res. 22 Dec 2021; 14: 7191–7224. (綜述針灸抗炎的神經免疫機制)
5. Liu, S., Wang, Z. F., Su, S. H., et al. Acupuncture at ST36 Ameliorates Acute Inflammation via the Vagus Nerve and Dopamine-mediated Anti-inflammatory Pathway. Nature Medicine. 2014; 20(3): 291–295. (Classic study confirming ST36 activates the vagus nerve anti-inflammatory pathway)
   Liu, S., Wang, Z. F., Su, S. H., et al. Acupuncture at ST36 Ameliorates Acute Inflammation via the Vagus Nerve and Dopamine-mediated Anti-inflammatory Pathway. Nature Medicine. 2014; 20(3): 291–295. (經典研究，證實 ST36 啟動迷走神經抗炎通路)