The eight extra meridians are; the Du (GV), the Ren (CV), the Chong, the Dai, the Yinwei, the Yangwei, the Yinqiao and the Yangqiao. These meridians have their own separate pathways and differ from the 12 main meridians. They do not pertain to any zangfu organs and they are not necessarily arranged in pairs externally. Because of these differences, they are called extraordinary meridians.
The differences between the main and extra meridians is as follows.
The eight extras have no direct association with any zangfu organ (internal bodily organ such as heart). However, the Du (GV) meridian curves around the kidney and passes through the heart system.
The 12 main meridians are all associated with an internal organ.
The eight extras are not externally/internally related.
The 12 mains meridians are Externally/internally related.
The eight extra meridians have no points of their own other than those on the Du and Ren meridians.
The 12 main meridians all have their own particular points along the meridian.
The distribution of the eight extra meridians runs from the lower parts of the body to the upper except for the Chong and Dai mai.
With the 12 main meridians, the distribution runs both upwards and downwards.
The eight extra meridians have no distribution with the upper limbs.
The 12 main meridians have distribution to both upper and lower limbs.
The Du, Ren, Chong and Dai meridians are single meridians while the Yinqiao, Yinwei, Yangqiao and Yangwei are distributed in pairs.
With the 12 main meridians, all meridians are in pairs, one on either side of the body.
The course of the eight extra meridians are distributed along the 12 main meridians. They function in regulating the blood and Qi circulation of the 12 main meridians. Should there be an excess of Qi and blood in the 12 main meridians, it is infused into the eight extra meridians and stored there until needed by the 12 main meridians again.
The Du mai or GV meridian is often referred to as Athe sea of yang meridians because the three yang meridians of both foot and hand converge into the Du meridian at GV 14. It regulates the circulation of Qi and blood in the Yang meridians so has the function of governing all the yang meridians.
The functions of the GV meridian are to regulate the circulation of blood and Qi in the Yang meridians. To regulate the functional activities of the brain and the spine marrow. To regulate the function of the urinary and reproductive systems.
When the GV meridian is out of order, symptoms such as opisthotonos (a position of the body where the head and neck and back are arched backwards as in tetanus) and syncope (fainting) can occur.
A disorder along this meridian can cause stiffness at the nape of the neck.
The general functions are: Binding together of all the meridians in the body. And to control leukorrhoea in females.
The Ren (CV) Meridian
This meridian dominates the yin of the whole body. Because of this, it is also known as Athe sea of yin meridians. The three yin meridians of the hand and the three yi meridians of the foot all join at CV 3. This meridian originates in the uterus and is especially connected with conception. Hence its name of Conceptor vessel.
Its function is to regulate the circulation of blood and Qi in the yin meridians. IT regulates the menstrual flow, dominates the reproductive system and the foetus. Regulates the Qi circulation of the chest, promotes the function of spleen and stomach and generally strengthens the body.
When this meridian is diseased, abnormal masses occur like hernia in males and splenomegaly in females. (Enlargement of the spleen).
The Chong Mai.
Chong means vital. It dominates the circulation of Qi and blood in 12 main meridians so it is often called, Athe sea of the 12 main meridians.
The functions are to regulate the circulation of the Qi and blood to the 12 main meridians. Regulates the menstrual flow. It regulates the ascending and descending of Qi in the body.
When this meridian is diseased, stagnation of the Qi will occur. Disorders of the reproductive system.
The Dai Mai.
Meaning >belt or girdle meridian, its function is to bind up (like a belt) all the other meridians. It is the only meridian that runs transversely across the surface of the body.
The general functions are to bind up the other meridians and to control leucorrhoea in females.
When this meridian is diseased, there will be pain and weakness in the lower back, distension of the abdomen, prolapse of the uterus, weakness of the waist.
The Yangqiao and Yinqiao Meridians
AQiao means heel. Meaning the capacity to raise the foot. Both of these meridians promote motility. (motion).
These meridians dominate the opening and closing of the eye lids with both meridians circling the eye to enter the brain. Both meridians have a relationship with sleep with the yangqiao meaning yang Qi. Hyperactive yang Qi leads to restless sleep, eyes open etc. Yinqiao means yin Qi and when the yin Qi becomes hyperactive, it leads to lassitude, closed eyes and somnolence.
When both meridians are normal, the body is active, alert with good sleep and good mobility. When these two meridians are in balance, the whole balance between yin and yang Qi in the body is maintained.
The Yinwei and Yangwei meridians
Wei means connection indicating that all the yin meridians connect to the yinwei while the yang meridians connect to the yangwei meridians.
The functions of this pair is to connect all the yin and yang meridians together. The yinweimai dominates the internal aspects of the body while the yangweimai dominates the external aspects of the body.
When these two meridians are working normally, there is balance between yin and yang in the body.
If the Yinweimai is diseased, pain in the heart is the result. If the Yangweimai is diseased, the body is open to invasion of exogenous cold or heat.