How Acupuncture Works–Without the Mumbo Jumbo
Western Veterinary Conference 2006
Narda G. Robinson, DO, DVM
Colorado State University
Fort Collins, CO, USA
Objectives of the Presentation
- Present information regarding the scientific basis of acupuncture.
- Dispel notions that acupuncture is an “energy” medicine.
General Key Points
- Acupuncture works not by stimulating invisible energy through invisible meridians, but by stimulating nerve fibers which induce physiologic repercussions.
Overview of the Issue
Chinese medicine, which includes acupuncture, began as early as five thousand years ago.1 Termed “acupuncture” by the West, needling therapy stimulates specific sites on the body called acupuncture points. Over time, the Chinese medical theories developed by ancient Chinese physicians incorporated increasingly sophisticated concepts of anatomy and physiology.2
Acupuncture involves the insertion of thin sterile needles or other means of body stimulation (e.g., heat therapy/moxibustion, electrical stimulation, low-level laser therapy3, etc.) into points on the body that produce physiologic changes locally and often systemically. Physicians and scientists recognized decades ago that the body displays organized physiologic reactions to somatic stimulation; scientific research done over the past several decades is providing mounting and detailed documentation of these effects.
Many of these reflexes travel via longitudinal connections contained within the spinal cord; early Chinese physicians drew the external, or somatic, relationships of these internal trajectories as acupuncture channels located on the body surface. These familiar linear patterns are now known as “channels” or “meridians”.
While ancient insights into these connections arose largely through close observation of stimulus-response patterns, acupuncturists were aware of significant features of the underlying anatomy. The close association of acupuncture channels to the vessels and nerves beneath the channels signifies the connection between structure (vessels and nerves) and function (reflex responses to somatic stimulation) understood long ago.
Acceptance of acupuncture as a valid medical therapy has outpaced other complementary medical approaches, largely due to the weight of evidence supporting its physiologic effects and clinical benefits. Since former President Nixon’s trip to China in 1971, physicians and scientists have studied acupuncture intensively.
In 1997, the National Institutes of Health issued a consensus statement of acupuncture, reflecting the assessment by a nonadvocate, non-Federal panel of experts of the medical knowledge available at the time. According to the Consensus Statement, “[P]romising results have emerged, for example, showing efficacy of acupuncture in adult postoperative and chemotherapy nausea and vomiting and in postoperative dental pain. There are other situations, such as addiction, stroke rehabilitation, headache, menstrual cramps, tennis elbow, fibromyalgia, myofascial pain, osteoarthritis, low back pain, carpal tunnel syndrome, and asthma, in which acupuncture may be useful as an adjunct treatment or an acceptable alternative or be included in a comprehensive management program. Further research is likely to uncover additional areas where acupuncture interventions will be useful.”
Acupuncture works by stimulating physiologic processes through neural signaling–not by moving invisible energy through invisible meridians as some claim. The unfortunate “conversion” of acupuncture into a metaphysically based approach occurred in the 1900s due to the influence of a French bank clerk, George Soulié de Morant. According to a leading Chinese medicine historian, “Soulié de Morant introduced “energy” as his interpretation and translation of the Chinese concept of Qi since he was convinced that science would one day be able to demonstrate the effects of acupuncture on energetic currents within the body. Since then, most literature written for European and American practitioners of acupuncture have interpreted the effects of needles in terms of energetic processes. (Italics added for emphasis.) For the supposed pathways of qi deep in the body, Soulié de Morant coined the term “meridian,” which despite its lack of faithfulness to the underlying Chinese concepts, has been retained by nearly all authors writing for a Western public.”4
In contrast to the commonly held but mistaken assumption that acupuncture “moves stuck energy”, the original goal appeared to be bloodletting.5 The channels, which Soulié de Morant re-named “meridians”, related anatomically to arteries and veins, which the acupuncture instruments punctured. Further, as Epler outlined clearly in his treatise “Bloodletting in early Chinese medicine and its relation to the origin or acupuncture”, “The vessels are organic structures, not functional pathways as they were later to become, blood is a fluid, and pneuma is, certainly in part, a material substance, not the “energy” it was later to become.”6 And, according to Kendall, the “vessels” referred to in Chinese acupuncture classics included nearby nerves: “Hence, nodes [i.e., acupuncture points] represent neurovascular concentrations of fine vascular structures and related nerves…these nodes require neural and vascular participation in order to function.]7
Some assert, again incorrectly, that the ancient Chinese people never performed anatomical investigations.8 Kendall, in the Dao of Chinese Medicine, Understanding an Ancient Healing Art, offers two possible reasons for this misconception.9 Either historians mistakenly assume that since Confucian teachings proscribed postmortem dissections, the Chinese people never performed them or they claim that, because ancestor worship pervaded the culture especially strongly many centuries ago, dissecting the body after death would invite a great degree of ancestral displeasure. However, Kendall points out, postmortem autopsy likely occurred long before Confucius existed (551-479 BCE), and still took place during his lifetime. Furthermore, the prohibition on autopsies that occurred in some dynasties happened several hundreds of years after the studies mentioned in the Huangdi Neijing (or, Yellow Emperor’s Internal Classic, ca. 300 BCE) were performed.
The Importance of Nerves in Acupuncture
Many authors have written about the central role of nerves and the nervous system in acupuncture10-18. A large body of evidence indicates that acupuncture points have abundant innervation. According to Chen Shaozong, “For 95% of all points in the range of 1.0 cm around a point, there exist nerve trunks or rather large nerve branches.”19
While some researchers have focused on the proximity of connective tissue planes and acupuncture points, they too recognize that the end result of needle stimulation involves signal transduction via needle tugs on collagen fibers, which ultimately invoke neuromodulation.20-23 Close examination of acupuncture points reveals many occur at sites of excitable muscle/skin-nerve complexes, replete with high densities of nerve endings.24
Nerves and nerve fibers convey the acupuncture stimulus to local and global nerve centers, providing analgesia and relief of muscle tension. 25-27 Specific neural features of acupuncture points help to explain the bioelectric characteristics associated with acupuncture points.28-30 Somato-autonomic reflexes produced by the somatosensory stimulation of acupuncture needling influence a multitude of functions, including cardiac, gastrointestinal, circulatory, cerebral, genitourinary, endocrine, and immune system activity.31 By beneficially influencing several neurophysiologic pathways either simultaneously or in series, acupuncture produces physiologic effects that help the individual maintain or restore health.32-33
In oversimplified terms, acupuncture imparts an afferent signal that begins locally (i.e., near the site of needling) and travels centripetally (i.e., to the spinal cord). Connections at the spinal level can have several results. For example, they may 1) send efferent signals back out to the periphery (leading to antidromic activation of free nerve endings at the site of needling), 2) loop into related visceral neural networks and alter internal organ function in a spinal segmental manner, 3) foster endogenous opioid release in the dorsal horn of the spinal cord to reduce spinal facilitation, or “wind-up”, and block pain, or 4) link to higher centers in the brainstem and cerebrum, influencing brain function and hormonal regulation.
The scientific basis of acupuncture is well-established. Acupuncture is neither “energy-medicine” nor a metaphysical medical approach. Instead, it is a means of interacting with the body’s physiological pathways by activating specific neural systems.
1. Kendall DE. Dao of Chinese Medicine–Understanding an Ancient Healing Art. New York: Oxford University Press, 2002. P. 1.
2. Kendall DE. Op cit., p. 31.
3. Posten W, WRone DA, Dover JS, Arndt KA, Silapunt S, and Alam M. Low-level laser therapy for wound healing: mechanism and efficacy. Dermatol Surg. 2005;31:334-340.
4. Unschuld PU. Chinese Medicine. Brookline: Paradigm Publications, 1998. Pp. 106-107.
5. Epler D. Bloodletting in early Chinese medicine and its relation to the origin of acupuncture. Bulletin of the History of Medicine. 1980;54(3): 337-367.
6. Epler D. Bloodletting in early Chinese medicine and its relation to the origin of acupuncture. Bulletin of the History of Medicine. 1980;54(3): 337-367.
7. Kendall DE. Op. cit., p. 2.
8. Kendall DE. Op cit., p. 32.
10. Mann F. Acupuncture–The Ancient Chinese Art of Healing and How It Works Scientifically. New York: Random House, Inc., 1962.
11. Matsumoto T and Lyu B. Anatomical comparison between acupuncture and nerve block. The American Surgeon. 1975;41:11-16.
12. Dung HC. Anatomical features contributing to the formation of acupuncture points. American Journal of Acupuncture. 1984; 12:139-143.
13. Gunn CC, Ditchburn FG, King MH, and Renwick GJ. Acupuncture loci: a proposal for their classification according to their relationship to known neural structures. American Journal of Chinese Medicine. 1976;4:183-195.
14. Filshie J and White A. Medical Acupuncture, A Western Scientific Approach. London: Churchill Livingstone, 1998.
15. Wong JY. A Manual of Neuro-Anatomical Acupuncture. Volume I: Musculoskeletal Disorders. Toronto: The Toronto Pain and Stress Clinic, Inc., 1999.
16. Wong JY. A Manual of Neuro-Anatomical Acupuncture. Volume II: Neurological Disorders. Toronto: The Toronto Pain and Stress Clinic, Inc., 2001.
17. Fu H. What is the material base of acupuncture? The nerves! Medical Hypotheses. 2000;54:358-359.
18. Cho ZH, Wong EK, and Fallon J. Neuro-Acupuncture. Scientific Evidence of Acupuncture Revealed!. Los Angeles: Q-Puncture, Inc., 2001.
19. Shaozong C. Modern acupuncture theory and its clinical application. (Chapter 5 The Morphologic Relationship between Points and Nerves). International Journal of Clinical Acupuncture. 2001;121(2):149-158.
20. Konofagou EE and Langevin HM. Using ultrasound to understand acupuncture. IEEE Engineering in Medicine and Biology Magazine. 2005: March/April: 41-46.
21. Langevin HM, Churchill DL, and Cipolla MJ. Mechanical signaling through connective tissue: a mechanism for the therapeutic effect of acupuncture. The FASEB Journal. 2001; 15:2275-2282.
22. Langevin HM, Churchill DL, Wu J, Badger GJ, Yandow JA, Fox JR, and Krag MH. Evidence of connective tissue involvement in acupuncture. FASEB J. (April 10, 2002) 10.1096/fj.01-0925fje.
23. Langevin HM, Churchill DL, Fox JR, Badger GJ, Garra BS, and Krag MH. Biomechanical response to acupuncture needling in humans. Journal of Applied Physiology. 2001;91:2471-2478.
24. Li A-H, Zhang J-M, and Xie Y-K. Human acupuncture points mapped in rats are associated with excitable muscle/skin-nerve complexes with enriched nerve endings. Brain Research. 2004;1012:154-159.
25. Dung HC. Anatomical features contributing to the formation of acupuncture points. American Journal of Acupuncture. 1984; 12:139-143.
26. Matsumoto T and Lyu B. Anatomical comparison between acupuncture and nerve block. The American Surgeon. 1975;41:11-16.
27. Shaozong C. Modern acupuncture theory and its clinical application (Chapter 5 The Morphological Relationship between Points and Nerves). International Journal of Clinical Acupuncture. 2001;12:149-157.
28. Croley TE and Carlson M. Histology of the acupuncture point. American Journal of Acupuncture. 1991;19:247-253.
29. Ionescu-Tirgoviste C. Anatomic and functional particularities of the skin areas used in acupuncture. American Journal of Acupuncture. 1975;3:199-206.
30. Still J. Acupuncture treatment of thoracolumbar disc disease: a study of 35 cases. Companion Animal Practice. 1988A;2:19-24.
31. Kimura A and Sato A. Somatic regulation of autonomic functions in anesthetized animals–Neural mechanisms of physical therapy including acupuncture. Jpn. J Vet. Res. 1997;45:137-145.
32. Kendall DE. The Dao of Chinese Medicine–Understanding an Ancient Healing Art. Oxford: Oxford University Press, 2002; pp. 1-15.
33. Jang I, Cho K, Moon S, Ko C, Lee B, Ko B, and Lee C. A study on the central neural pathway of the heart, Nei-Kuan (EH-6) and Shen-Men (He-7) with neural tracer in rats. Am J Chin Med. 2003;31(4):591-609.