From "In Touch Zhejiang" magazine, November 2005

Mai oh mai oh mai
Points of contention needle skeptical minds

In last month's article I stated that the "mai" ("vessels" being my translation; "meridians" or "channels" as some others would have it) were in fact the blood vessels and not invisible "meridians" circulating Qi and blood through the body. Some readers may have been relieved to hear this and others may have cursed me for being reductionistic. If in fact you are of the latter camp, you are correct to say this view is somewhat reductionistic.

That said, the ancient Chinese were still likely describing anatomical blood vessels- yes, as in, the flexible little pipes that enable blood flow. So which is it, blood vessels or meridians? In Chinese medicine when an “either or" question is posed, the answer is often a perplexing, "Yes", meaning, "Yes, it is both this and that." However, taking "this" as the blood vessels, "that" is still not invisible meridians. And this leads us to the first of three questions that are the topic of this essay: What exactly are the “mai”?

The second issue is this: If, on the subject of anatomical entities, the “mai” are in fact blood vessels, is the acupuncturist sticking needles into (gulp!) the blood vessels? Thirdly, how in any case does acupuncture work?

Here’s the situation: The “mai” are indeed the blood vessels, but they are more than that. This, by the way, is typical of Chinese medicine: the functions attributed to the organs by the ancient Chinese do not necessarily correlate with modern understanding of physiology, although we should not infer from this that the ancient Chinese were wrong. Their paradigms for anatomy and physiology are unsurprising, since the ancients didn’t have the hardware that makes possible the study of anatomy and physiology at a microbiological level. They were relying instead upon outwardly observable physiological phenomenon gleaned through the “four methods” of examination (looking, smelling/listening, asking, and palpating) in their efforts to develop their physiological model.

Some people have called the result a “physiology of systematic correspondences”. In this model, the various systems (organs, vessels, etc.) are based upon “correspondences”, i.e. related physiological phenomenon, and not solely, as in modern medicine, on the physiological function of the anatomical structures themselves. For example, a phenomenon like dry eyes could be attributed to the liver, and insomnia could be attributed to the heart. Modern physiology would say this is incorrect, but the point is that the Chinese idea of the organs is different than that of Western medicine. The “mai” therefore are in fact a physiological system of corresponding phenomenon, not just the anatomical blood vessels. Whew. If you’ve made it this far the rest is easy.

OK, so aside from blood vessels, what are the “mai”? Let’s first look at what the ancient Chinese had to say, then, at the risk of being reductionistic, we can try to make some correlations to modern physiology. According to the ancient Chinese, the “mai” are a network that links all the parts of the body together- the interior of the body is connected to the exterior, the top to the bottom, the back to the front, the right to the left, and the organs to their related parts and to each other, and so on. This looks a lot like the nervous system, which we know is a sort of communication network in the body, and as it turns out, the nervous system is heavily involved in the physiology of acupuncture and thus the “mai” themselves. In addition, the “mai” distribute nutrients to all the parts of the body. This looks a bit like the cardiovascular system, distributing nutrients such as glucose and oxygen throughout the body via the blood and blood vessels. Of course it would, again, be reductionist to say that the “mai” are simply the blood vessels and nerves, and as we will see in the following discussion of how acupuncture works, there is much more than these two systems involved in the physiological response to acupuncture.

So what exactly is happening inside the body upon insertion of an acupuncture needle? Again, there are two ways to explain this- first according to the ancient Chinese, and second (anti-reductionists cringe here) according to modern physiology. The traditional explanation, very simply put, is that the needles regulate the flow of Qi and blood in the body, and since all illness is, again simply put, due to disharmony in the flow of Qi and blood, acupuncture can be used to treat disease. The modern explanation is extremely long and requires a solid background in anatomy and physiology to be understood, but here’s a brief synopsis.

First of all, in answer to the previously posed question, the needles are not being inserted into blood vessels (big sigh of relief here)- well, not vessels of any significant size, anyway. They are however touching capillary beds, which are dense networks of extremely fine blood vessels. In fact, what sets an acupuncture point apart from other places in the body is its high density of capillaries and nerves. This is what makes it more responsive to the needle. The needle touches this spot, stimulating the nervous system to send a signal to the brain informing of the breach of the skin by a foreign object. The brain then sends descending control signals back to the insertion point to help mediate the defense response that the body is mounting against the foreign body. Because of the highly integrated nature of the nervous system, the descending control signals from the brain also travel to and affect other parts of the body. This, however, is not random, and the ancient Chinese mapped out these affects in great detail.

Interestingly, much of what they noted corresponds with modern understanding of the nervous system. For example, there are points on the upper part of the back that are used to treat ailments of the lung and heart. This is the region where nerves exit the spine to innervate those organs. Obviously, the Chinese had very early on developed a basic understanding of the nervous system, which they, at least in part, attributed to the “mai”. So the “mai” are in fact a conglomeration of various structures and functions belonging, but almost certainly not limited to the blood, vascular, nervous, and immune systems.

So what is the point of this sort of analysis? In order to develop a deeper and more comprehensive understanding of Chinese medicine, and medicine and the human body in general, it is important to use all available tools and knowledge. Traditional Chinese physiology and modern biomedical physiology are both valid, but attempting to make direct correlations between the two is difficult and we run certain risks- crude reductionism being one of them. Part of the problem lies in the fact that the field of modern biomedical physiology is still under development and there are many things that cannot be explained using that model.

Therefore we should not be looking for a complete biomedical explanation of Chinese medicine, but never the less, a partial explanation can certainly be of use, and may even help guide clinical thinking and practice. As long as we proceed carefully, critically review our hypotheses, and avoid stubborn dogmatism, the combination of these two views leads to greater insight. And this brings us closer to our ultimate goal: the prevention and treatment of disease.

Copyright© 2005 Greg A. Livingston