Channels
The main channels permeate the body in the following two ways
1. The Yang channels control the exterior of the body, the Yin channels the interior. The exterior and interior channels are coupled in pairs. For instance the Large Intestine (Yang channel) is coupled with the Lung (Yin channel).
2. At the end of a channel, the circulation meets a channel of opposite Yin/Yang polarity.
3. There is a connection between arm channels and leg channels. This occurs in two place: one is on the head, where the  arm Yang meet the leg Yang, and the other on the front of the chest, where the arm Yin meet the leg Yin channels.

The main channels run both up and down the limbs, and the Qi flows from one channel into the next in succession, until the whole circuit is completed, thereafter flowing into the first one again. In half of the main channels (ie the three upper Yang and three lower Yin channels) the flow in centripetal; in the others it is centrifugal.


The connecting Channels.
The connecting channels are vessels which branch out from the Primary channels.The great majority are distributed superficially over the body.
Each of the twelve main channels has a Luo point and an associated Luo-connecting channel.
The function of the connecting channels are to connect Yin and Yang associated organ channels peripherally.
The fifteen larger Connecting channels are described below.

1. The Connecting Channel of the Lung. After separating from the Primary channel at point Lu 7- Lieque on the wrist, this Connecting channel travels to the Lrge Intestine channel. Another branch follows the Lung channel into the palm of the hand, where it spreads through the thenar eminence.
Symptoms of excess: hot palms or wrist
Symptoms of deficiency: shortness of breath, frequent micturition, enuresis.

2. After separating from the Primary channel at point Ht 5- Tongli on the wrist, this channel joint the Small Intestine channel. At about 11/2 units above the transverse crease of the wrist, the channel again separates from the Small Intestine channel and follows the Heart channel to the Heart itself. It then proceeds to the base of the tongue and connects with the eye.
Symptoms of excess: fullness and pressure in the chest.
Symptoms of deficiency: aphasia

3. The Connecting channel of the Pericardium- After separating from the Primary channel at point P 6- Neiguan on the wrist, this channel spreads out between the two tendon and follows the Pericardium channel upward to the Pericardium, after which it connects with the Heart.
Symptoms of excess: chest pains
Symptoms of deficiency: irritability

4. The Connecting channel of the Large Intestine- After separating from the Primary channel at point LI 6- Pianli on the wrist, this channel joints with the Lung channel. Another branch follows the arm to the shoulder, crosses the jaw and extends to the teeth. Still another branch separates at the jaw and enters the ear region.
Symptoms of excess: toothache, deafness.
Symptoms of deficiency: sensation of coldness in the teeth, fullness and congestion in the chest.

5. The connecting channel of the Small intestine- After separating from the Primary channel at point SI 7- Zhizheng on the forearm, this channel connects with the Heart channel. Another branch continues up the arm, crosses the elbow and joins with the shoulder.
Symptoms of excess: looseness in the joints, atrophy of the muscles in the elbow and arm.
Symptoms of deficiency: long finger-shaped warts, scabies.

6. The Connecting channel of the Triple Burner- After separating from the Primary channel at point TB 5- Waiguan on the wrist, this channel proceeds up the posterior aspect of the arm and over the shoulder, converging with the Pericardium channel in the chest.
Symptoms of excess; spasms of the elbow.
Symptoms of deficiency: flaccid muscles in the arm and elbow.

7. The Connecting channel of the Stomach- After separating from the Primary channel at point St40- Fenglong on the lower leg, this channel connects with the Spleen channel. A branch follows the lateral margin of the tibia upward across the branch separates in the neck and connects with the throat.
Symptoms of excess: epilepsy, insanity.
Symptoms of deficiency: flaccid or atrophied muscles in the legs or feet, pharyngitis, sudden aphasia.

8. The Connecting channel of the Bladder- This channel separates from the Primary channel at point Bl 58- Feiyang on the lateral aspect of the lower leg, then connects with the Kidney channel
Symptoms of Excess: nasal congestion, headache, back pain.
Symptoms of deficiency: clear nasal discharge, nosebleed.

9. The Connecting channel of the Gall Bladder- After separating from the Primary channel at point GB 37 Guangming on the lateral aspect of the lower leg, this channel connects with the Live channel, proceeds downward and disperses over the dorsum of the foot.
Symptoms of Excess: fainting
Symptoms of Deficiency: weak and flaccid muscles of the foot, making it difficult to stand