Classification and Distribution of Meridians and Acupoints

The channel-collateral system is primarily composed of the twelve regular channels, eight extraordinary channels and fifteen major collaterals. The twelve regular channels, combined with the Ren Channel and Du Channel (two of the eight extraordinary channels), are known collectively as the fourteen channels. Each channel is lined with specialized points for acupuncture and moxibustion therapy.

The twelve regular channels run symmetrically on both sides of the body. The three hand yin channels travel from the chest to the hands; the three hand yang channels extend from the hands to the head; the three foot yang channels descend from the head to the feet; and the three foot yin channels course from the feet toward the abdomen and chest. Both the Ren Channel and Du Channel start at the perineum, then ascend along the anterior midline and posterior midline of the body respectively.

Acupuncture points fall into three categories: fourteen-channel points, extraordinary points and Ashi points.

Fourteen-channel points account for the largest portion of all acupuncture points, with a total of 361 standard locations. Points along the twelve regular channels are bilateral and symmetric. In contrast, points on the Ren Channel and Du Channel are unilateral and situated along the anterior and posterior midlines separately.

Extraordinary points are clinically effective empirical points. They have fixed anatomical locations but are not incorporated into the fourteen-channel system.

Ashi points refer to tender or reactive spots triggered by disorders. They have no fixed positions or formal names, following the principle: “Where there is tenderness, there lies the acupuncture point.”

1. Overview

Meridians and collaterals form the core network of traditional Chinese medicine (TCM). They run throughout the human body to transport qi and blood, connect internal organs, limbs and body surfaces. Acupoints, also known as acupuncture points, are specific sites distributed along meridians where therapeutic stimulation such as acupuncture and moxibustion is applied.

2. Classification & Distribution of Meridians

2.1 Main Meridians (Twelve Regular Meridians)

The twelve regular meridians are the primary part of the meridian system, paired as six yin meridians and six yang meridians. They follow fixed routes and distribute symmetrically on both sides of the body.

• Yin Meridians: Mainly distributed on the medial sides of limbs, chest and abdomen. They correspond to zang-fu organs (solid organs).
• Yang Meridians: Primarily located on the lateral sides of limbs, head, face, back and outer trunk. They connect to fu organs (hollow organs).

These meridians run in a continuous cycle, linking the upper and lower body as well as the interior and exterior of the body.

2.2 Eight Extraordinary Meridians

This group consists of eight unique meridians independent of the twelve regular meridians. They do not connect directly with zang-fu organs and have no paired circulation.

• Distribution: Mainly travel along the midline of the body, the lumbosacral region and the trunk.
• Functions: Regulate qi and blood of the twelve regular meridians, and govern special physiological activities. The most commonly used are the Governor Vessel and Conception Vessel, which carry their own independent acupoints.

2.3 Collaterals

Collaterals are branch vessels diverging from meridians, dividing into large collaterals, minute collaterals and superficial collaterals. They spread all over the body surface to interconnect the entire meridian system.

3. Classification & Distribution of Acupoints

Based on their affiliation and distribution rules, acupoints are divided into three major categories in international acupuncture standards.

3.1 Meridian Acupoints

Also called regular acupoints. They lie precisely on the pathways of the twelve regular meridians, the Governor Vessel and the Conception Vessel.

• Features: Fixed locations, clear meridian attribution and definite therapeutic effects.
• Distribution: Cover the head, face, trunk, limbs and joints across the whole body. This is the largest category of clinical acupoints.

3.2 Extraordinary Points (Extra-Meridian Points)

These effective clinical points are not attached to any of the standard meridians.

• Distribution: Mostly concentrated on the head, neck, ears, hands and feet.
• Features: Distinct locations and remarkable curative effects for specific diseases. Many eye-related and pain-relief points belong to this category.

3.3 Ashi Points (Tender Points)

They have no fixed names or standard locations. Any tender spot, sore area or reactive point triggered by illness is defined as an Ashi point.

• Distribution: Appear locally around lesions, pain areas or affected tissues.
• Features: Widely used for pain management, soft tissue injuries and local disorders.

4. General Distribution Rules of Acupoints

1. Head and Face: Acupoints gather densely around the eyes, nose, mouth, ears and scalp, mainly for treating local facial, ocular and neurological disorders.
2. Trunk: Points on the chest and abdomen correspond to internal visceral disorders; points on the back are closely associated with zang organs.
3. Limbs: A large number of commonly used acupoints distribute on the upper and lower limbs. Distal limb points work for both local symptoms and systemic diseases of the head, trunk and internal organs.