Acupuncture Acupuncture is the procedure of inserting and manipulating needles into various points on the body to relieve pain or for therapeutic purposes. The earliest written record of acupuncture is the Chinese text Shiji (Records of the Grand Historian) with elaboration of its history in the second century BCE medical text Huangdi Neijing (Yellow Emperor's Inner Canon). Different variations of acupuncture are practiced and taught throughout the world. Acupuncture has been the subject of active scientific research both in regard to its basis and therapeutic effectiveness since the late 20th century, but it remains controversial among medical researchers and clinicians. Research on acupuncture points and meridians is preliminary and has not conclusively demonstrated their existence or properties. Clinical assessment of acupuncture treatments, due to its invasive and easily detected nature, makes it difficult to use proper scientific controls for placebo effects. The World Health Organization and the United States' National Institutes of Health (NIH) have stated that acupuncture can be effective in the treatment of neurological conditions and pain, though these statements have been criticized for bias and a reliance on studies that used poor methodology. Reports from the USA's National Center for Complementary and Alternative Medicine (NCCAM), the American Medical Association (AMA) and various USA government reports have studied and commented on the efficacy (or lack thereof) of acupuncture. There is general agreement that acupuncture is safe when administered by well-trained practitioners using sterile needles, and that further research is needed. Acupuncture points and meridians Classical texts describe most of the main acupuncture points as existing on the twelve main and two of eight extra meridians for a total of fourteen "channels" through which qi and Blood flow. Other points not on the fourteen channels are also needled. Local pain is treated by needling the tender "ashi" points where qi or Blood is believed to have stagnated. The zang-fu of the twelve main channels are Lung, Large Intestine, Stomach, Spleen, Heart, Small Intestine, Bladder, Kidney, Pericardium, Gall Bladder, Liver and the intangible San Jiao. The eight other pathways, referred to collectively as the qi jing ba mai, include the Luo Vessels, Divergents, Sinew Channels, ren mai and du mai though only the latter two are needled. The remaining six qi jing ba mai are manipulated by needling points on the twelve main meridians. Normally qi is described as flowing through each channel in a continuous circuit. In addition, each channel has a specific aspect and occupies two hours of the "Chinese clock". The zang-fu are divided into yin and yang channels, with three of each type located on each limb. Qi is believed to move in a circuit through the body, traveling both superficially and deeply. The external pathways correspond to the acupuncture points shown on an acupuncture chart while the deep pathways correspond to where a channel enters the bodily cavity related to each organ. The three yin channels of the hand (Lung, Pericardium, and Heart) begin on the chest and travel along the inner surface of the arm to the hand. The three yang channels of the hand (Large Intestine, San Jiao, and Small Intestine) begin on the hand and travel along the outer surface of the arm to the head. The three yin channels of the foot (Spleen, Liver, and Kidney) begin on the foot and travel along the inner surface of the leg to the chest or flank. The three yang channels of the foot (Stomach, Gallbladder, and Urinary Bladder) begin on the face, in the region of the eye, and travel down the body and along the outer surface of the leg to the foot. Each channel is also associated with a yin or yang aspect, either "absolute" (jue-), "lesser" (shao-), "greater" (tai-) or "brightness" (-ming). The theory of the channels is interrelated with the theory of the Organs. Traditionally, the internal Organs have never been regarded as independent anatomical entities. Rather, attention has centered upon the functional and pathological interrelationships between the channel network and the Organs. So close is this identification that each of the twelve traditional Primary channels bears the name of one or another of the vital Organs. In the clinic, the entire framework of diagnostics, therapeutics and point selection is based upon the theoretical framework of the channels. "It is because of the twelve Primary channels that people live, that disease is formed, that people are treated and disease arises.". From the beginning, however, we should recognize that, like other aspects of traditional medicine, channel theory reflects the limitations in the level of scientific development at the time of its formation, and is therefore tainted with the philosophical idealism and metaphysics of its day. That which has continuing clinical value needs to be reexamined through practice and research to determine its true nature. The meridians are part of the controversy in the efforts to reconcile acupuncture with conventional medicine. The National Institutes of Health 1997 consensus development statement on acupuncture stated that acupuncture points, Qi, the meridian system and related theories play an important role in the use of acupuncture, but are difficult to relate to a contemporary understanding of the body.[5] Chinese medicine forbade dissection, and as a result the understanding of how the body functioned was based on a system that related to the world around the body rather than its internal structures. The 365 "divisions" of the body were based on the number of days in a year, and the twelve meridians proposed in the TCM system are thought to be based on the twelve major rivers that run through China. However, these ancient traditions of Qi and meridians have no counterpart in modern studies of chemistry, biology and physics and to date scientists have been unable to find evidence that supports their existence.