Historical background

Acupuncture has increasingly been used in Western medicine over the last three decades. It originated with traditional Chinese medicine (TCM) in the early Han period and has been described systematically for the first time in the medical compilation “Huangdi Neijing” (Yellow Emperor’s Inner Classic), whose texts date from the Han period (200 BCE to 200 CE) (Zhu 2001). Acupuncture means in its Chinese translation zhen jiu “needling burning”. However, before the development of steel needles, acupuncture consisted of skin irritation using sharp objects (e.g., stones), local warming at defined body sites, and minimal surgical interventions like blood letting.

Nowadays, acupuncture is defined as needling at anatomically defined sites of the body (acupuncture points) or sensitive spots (ah shi points) for therapeutic purposes including so-called moxibustion, i.e., heating or warming of the skin at acupuncture points with the help of burning mugwort (Artemisia vulgaris) (Fig. 7.9.1).

Acupuncture includes different techniques of needle stimulation, e.g., repetitive thrusting, twisting, rotating, or electrical stimulation to achieve different treatment effects according to the theoretical background.

There are different acupuncture related techniques such as laser acupuncture, injection in acupuncture points, and acupressure. A huge body of further manual or tool-assisted treatment approaches are based on the concept of acupuncture points and meridians.

The theoretical background of acupuncture is based on Chinese, Confucian-legalistic, social and political philosophy of the first century CE. Medical acupuncture is based on the subjective aspects of disease, in contrast to the diagnostic and therapeutic understanding in western medicine, which is based on objective measurable pathologies. Acupuncture consists of systematic analogy expressed in the early concepts of yin and yang, qi and the internal organs, and results of detailed observations of nature and life.

Physiologic background

Acupuncture effects are mediated through different neurophysiologic mechanisms: activation of mechano- and nociceptors, descending inhibitory pathways (comprising diffuse noxious inhibitory controls), or spinal and supraspinal modulation form some of the explanations to describe local and distant needling effects. Basic research showed the release of different neurotransmitters (e.g., norepinephrine (noradrenaline), serotonin), hormones (e.g., estrogen, cortisol), and peptides (e.g., endorphin) to be related to acupuncture treatment. Nevertheless, there is no single course of action that explains the complex neurophysiologic and anatomic responses to acupuncture treatment.

Acupuncture points have been supposed to be spots characterized by a high density of neural receptors. In addition, acupuncture points have been found to be situated next to vascular, nerve, and ligamentous sheets, despite there being more than 10 000 sheets in the superficial fascia of the human body, most of them not correlating with an acupuncture point. Studies of electrical properties of acupuncture points have shown that the electrical skin resistance at these points can be increased or decreased when compared to the surrounding skin area. None of those findings was able to define acupuncture points anatomically.

A remarkable observation to explain acupuncture points and meridians comes from myofascial referred pain that was observed to spread along the supposed meridian courses. Dorsher & Fleckenstein (2008a, 2008b) compared the anatomic correspondence of the “common” myofascial trigger point locations described in the Myofascial Trigger Point Manual to the locations of classical acupuncture points (Fig. 7.9.3). Anatomic correspondence of a common myofascial trigger point and a classical acupuncture point means those points are proximate and are demonstrated by acupuncture and anatomy references to enter the same muscle region. There is at least a 93.3% correspondence, if the distance between points on the skin is at most 3 cm; anyhow, points had to enter the same muscle region. At a maximum skin distance of 1 cm, 37% of points can still be found to correspond. There are marked clinical correspondences of both the pain indications (up to 97%) and somatovisceral indications (> 93%) of anatomically corresponding common myofascial trigger point–classical acupuncture point pairs (classical acupoints that are proximate to and enter the muscle region of their correlated common myofascial trigger points). The spread of deqi along the meridians seems to be the same phenomenon as the physiologically analogous concept of referred pain arising from myofascial trigger points in the myofascial pain tradition. This provides a clinical line of evidence that myofascial trigger points and acupuncture points likely might describe the same physiologic phenomena.

These correlations make the explanation of the connecting meridians between acupuncture points more feasible. Speculation in this regard has continued since acupuncture’s earliest days as to whether acupuncture meridians are conceptual constructs or have an anatomic basis. Connective tissue might mediate acupuncture effects: Langevin (2002a) showed that rotation after needling activates fibroblast by mechanosensory transduction. These local effects can be tracked in distant connective tissue, too. Additionally, some researchers have described a degree of overlap of meridians and the peripheral nervous system in the extremities, whereas others have postulated that the meridians may exist in the myofascial layer of the body, reflecting perceived sensations by stimulating fascial structures. An interesting observation might be that anatomically derived myofascial meridians have distributions similar to those of acupuncture meridians described by TCM.

However, it remains clear that the target tissue of acupuncture points varies, comprising not only myofascial trigger points but also nerves, bones, ligaments, vessels, and the autonomic nervous system.