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Anat Rec (Hoboken). 2021 Nov;304(11):2372-2380
Interpretation of acupoint location in traditional Chinese medicine teaching: Implications for acupuncture in research and clinical practice

Yi Zhang
Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.

Abstract

Acupuncture is a therapeutic intervention of traditional Chinese medicine, characterized by the insertion of a fine metal needle through the human body's skin at an acupuncture point (acupoint). Acupuncture has become from cultural curiosity to fast-growing complementary and alternative medicine therapy worldwide, including in the United States. The ability to locate acupoints on the body surface precisely is critical for the acupuncture treatment. However, the location of acupoints varies frequently among practitioners. Therefore, in the present study, the author will address the application of acupoint in traditional Chinese medicine (including the anatomical location of acupoint) to draw attention to the issues about the acupoint location in acupuncture research and clinical practice. Moreover, further studies are needed to determine whether acupoint location with specificity could be validated by employing reliable tools. In the future, the incongruity among acupuncturists regarding acupoint location should be resolved, and the acupoint location methods with more accuracy should be developed.

https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.24618

Excerpts:

"The meridian theory, a fundamental of TCM, is an essential guide for diagnosis and treatment practices (Figure 3). The meridians are organized into a circuit in which blood and qi flow in different proportions (Figure 4). Qi is a multipurpose principle with no analogue in modern scientific and biomedical terminology that has been translated to use expressions, for example, vital force or energy (Marcelli, 2013). Since organs are interconnected through meridians, acupuncture could restore healthy organ function and body balance by affecting meridians (Efferth, Xu, & Lee, 2019). Despite considerable efforts to understand the anatomy and physiology of meridians and acupuncture points, the definition and characteristics of these structures have not been elaborated in detail (NIH Consensus Conference, 1998). The application of combined cutting-edge technologies (e.g., genomics, metabolomics, and system biological approaches) and TCM methodologies will help and deepen the assessment of the therapeutic effects and possible action mechanisms of acupuncture, thus bridging the gap between traditional medicine and future medicine (Efferth et al., 2019; Wang et al., 2011). The shift from experience-based to evidence-based medicine will be an essential step forward.

"Acupuncture points, namely acupoints, are known as specific locations on the body that are needled during acupuncture treatment. According to the classical TCM theory, acupoints are linked together by a network of meridians running longitudinally on the body surface (Longhurst, 2010; Zhou & Benharash, 2014). Two articles published recently raise attention to the acupoints (Birch & Alraek, 2020; Lee, Kwon, & Chang, 2020; Lee, Ryu, & Chae, 2020). According to both traditional and contemporary theories, the ability to locate acupoints on the body surface precisely is critical for acupuncture treatment. However, acupoint location varies frequently among practitioners (Bäumler, Simang, Kramer, & Irnich, 2012; Godson & Wardle, 2020). Therefore, in anatomical teaching of acupuncture, especially during the learning and training of acupuncture in the medical schools or educational institutions of TCM, more emphasis should be placed on teaching exact acupoint location and their application in research and clinical practice."

"Although there have been reported benefits of acupuncture, the understanding regarding its mechanism of action still lags behind its wide usage, so the practitioners should be familiar with its potential clinical applications (Sierpina & Frenkel, 2005). In clinical practice, various forms of approaches can be used to stimulate acupoints to treat the disease."

[discussion of manual acupuncture, electroacupuncture, transcutaneous electrical acupoint acupuncture stimulation, moxibustion, and acupressure]

"Acu-magnet therapy includes stimulation of the acupoint with a static magnetic field generated by a permanent magnet (Colbert et al., 2008). Acupoint injection, also known as 'water needle,' is an intervention that includes injecting different types of substances (e.g., vitamins or herbal extracts) into the acupoint (Coyle, Liu, Zhang, & Xue, 2015; Huang et al., 2019). Acupoint autohemotherapy, also a kind of acupoint injection, involves injecting the patient's venous blood into acupoint (Hong et al., 2019). Acupoint herbal patching is a treatment method of externally applying a processed herbal patch to acupoint. It can be applied in children for its noninvasive, pain-free approach (Lee, Kwon, & Chang, 2020; Lee, Ryu, & Chae, 2020; Wei, Zhang, Li, & Li, 2020). Acupoint catgut embedding is a kind of modern acupuncture. It needs sterile forceps to implant the absorbable catgut sutures into the acupoint based on the theory of acupuncture (Li et al., 2020; Sheng, Jin, Zhu, Chen, & Liu, 2019). Laser acupuncture is a relatively young modality in acupuncture that includes photonic stimulation of acupoint and has been used successfully for the treatment of various conditions (Litscher, 2018).

"So far, the traditional and primary method for acupoint location is the Cun measurement system, including the finger Cun measurement (directional method) and the bone proportional Cun measurement (proportional method). The directional method measures the required number of units from an anatomical landmark or reference point to an acupoint using Cun reference measurement (Chao & Wang, 2010). The transverse diameter of the interphalangeal joint of the thumb is taken as a unit of measurement of one Cun; and the transverse diameter of the remaining four fingers (the index finger, middle finger, ring finger, and little finger) is taken as a unit of measurement of three Cun. The proportional method is another method of measuring the body by dividing the distance between two anatomical landmarks or reference points into an equivalent number of equal-sized sections (Park et al., 2006)."

"A recent systematic review has demonstrated that the directional method is not precise and accurate for locating the acupoints (Godson & Wardle, 2019). Consequently, it is recommended that the proportional method should be used in preference to the Cun-dependent directional method.

"It is not clear that acupoints are fixed in their location. From the earliest times, it is reasonable to think of the acupoints as not being of the anatomical structures they lie close to but rather as functional entities close to those structures that can be influenced by needles. For teaching purposes, the acupoint location should be fixed relative to nearby anatomical structures. Also, acupuncture needs to be formulated based on modern neuroanatomy and physiology rather than metaphysical concepts to improve our understanding of its mechanism of action (Cheng, 2011)...Once in the vicinity of the anatomical description, some practitioners insert the needle at that precise location. De qi (obtaining Qi) is a sensation experienced by a patient or an acupuncturist during treatment (Park et al., 2013)...If de qi is not found, the needle angle is changed until de qi is found. Thus, the actual location of the acupoint is not under the surface, but is within the area of anatomical description. This seems to be standard practice in TCM."

"To compare the location accuracy between directional and proportional methods, the bone length is calculated to locate acupoints using dual-energy X-ray absorptiometry (Park et al., 2006). Ultrasound imaging of acupoints is developed as a reliable and practical procedure for the accurate and safe insertion of needles (Kim et al., 2017). Before and after acupoint stimulation, the high-frequency power spectrum has been assessed by electroencephalography, and acupoint responses were found to be stable compared to stimulation elsewhere in the body (Choi et al., 2016). The skin oxygen (O2) density distribution has been monitored by high-sensitive electrochemical O2 microsensors to localize the acupoints (Lee, Lee, Park, Jang, & Jhon, 2009). Functional magnetic resonance imaging has also been used to demonstrate the specificity of acupoint location (Kong et al., 2009)."

"A growing body of research suggests that acupuncture is a kind of nociceptive stimulus that could amplify the cascade effects of an inflammatory response at the site around the acupoint, which in turn can activate the nerve-endocrine-immune system...By far, the most widely tested model is the neurostimulation model. In both humans and animals, acupuncture and electrical stimulation have demonstrated well-documented and reproducible effects on the central, peripheral, and autonomic nervous systems (Kaniusas et al., 2019; Napadow et al., 2008)."

"Despite advances in acupuncture research in recent decades, no conclusive results have been obtained regarding anatomical or physiological characteristics of acupoints. Researchers have speculated that acupoint location imprecision increases for points distant from the anatomical landmarks (Rivers & Zollman, 2013)."

"Concerning the high degree of variation in location, some researchers have initiated the idea that the term 'acupuncture field' is more appropriate for the clinical description of acupoints (Molsberger, Manickavasagan, Abholz, Maixner, & Endres, 2012)."

"In summary, identification of reliable and reproducible acupoints location is essential for acupuncture research and treatment. The present study focused on the issues regarding acupuncture research and clinical practice. Also, the author proposed that during acupuncture teaching in medical schools or educational institutions, more emphasis should be placed on the application of acupuncture based on the anatomical knowledge of acupoints location. Moreover, given the complexity of acupuncture theory, further research studies are needed to determine whether acupoints location could be validated by employing reliable tools. The incongruity among acupuncturists regarding acupoints location should be resolved, and more accurate acupoint location methods should be developed."