Acupuncture points and meridians

Most acupuncture points are found along the "fourteen channels", which are described in TCM as pathways through which Qi and Blood flow. There also exist "extra points" not belonging to any channel. Other tender points (known as "ashi points") may also be needled as they are believed to be where stagnation has gathered.

Treatment of acupuncture points may be performed along several layers of pathways, most commonly the twelve primary channels, or mai, located throughout the body. The first twelve channels correspond to systems of function: Lung, Large Intestine, Stomach, Spleen, Heart, Small Intestine, Bladder, Kidney, Pericardium, San Jiao (an intangible, also known as Triple Burner), Gall Bladder, and Liver. Other pathways include the Eight Extraordinary Pathways (Qi Jing Ba Mai), the Luo Vessels, the Divergents and the Sinew Channels. Ashi (tender) points are generally used for treatment of local pain.

Of the eight extraordinary pathways, only two have acupuncture points of their own: the Ren Mai and Du Mai, which are situated on the midline of the anterior and posterior aspects of the trunk and head respectively. The other six meridians are "activated" by using a master and couple point technique which involves needling the acupuncture points located on the twelve main meridians that correspond to the particular extraordinary pathway.

The twelve primary pathways run vertically, bilaterally, and symmetrically and every channel corresponds to and connects internally with one of the twelve Zang Fu ("organs"). This means that there are six yin and six yang channels. There are three yin and three yang channels on each arm, and three yin and three yang on each leg.

• The three yin channels of the hand (Lung, Pericardium, and Heart) begin on the chest and travel along the inner surface (mostly the anterior portion) 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 (mostly the posterior portion) 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 (mostly posterior and medial portion) 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 (mostly the anterior and lateral portion) of the leg to the foot.

The movement of Qi through each of the twelve channels comprises an internal and an external pathway. The external pathway is what is normally shown on an acupuncture chart and is relatively superficial. All of the acupuncture points of a channel lie on its external pathway. The internal pathways are the deep course of the channel where it enters the body cavities and related Zang Fu organs. The superficial pathways of the twelve channels describe three complete circuits of the body, chest to hands, hands to head, head to feet, feet to chest, etc.

The distribution of Qi through the pathways is said to be as follows (the based on the demarcations in TCM's Chinese Clock): Lung channel of hand taiyin to Large Intestine channel of hand yangming to Stomach channel of foot yangming to Spleen channel of foot taiyin to Heart channel of hand shaoyin to Small Intestine channel of hand taiyang to Bladder channel of foot taiyang to Kidney channel of foot shaoyin to Pericardium channel of hand jueyin to San Jiao channel of hand shaoyang to Gallbladder channel of foot shaoyang to Liver channel of foot jueyin then back to the Lung channel of hand taiyin. According to the "Chinese clock", each channel occupies two hours, beginning with the Lung, 3AM-5AM, and coming full circle with the Liver 1AM-3AM.