These two channels, the Yin Wei and Yang Wei, are the last of the Extraordinary Vessels. They work together as a connection between all the other channels of the body. The Yang Wei channel dominates the exterior part of the body, so it acts as a shield against influences coming into the body-aka, the common cold. If this channel has excess energy, the patient might have symptoms of dizziness, blurred vision, or asthma. If the channel is deficient in energy, the patient might be unable to get themselves off the couch, from a lack of physical and mental energy. Obsessive/compulsive disorders and manic-depression can also stem from a disturbance of this channel.
The Yin Wei is the Yang Wei's deeper paired channel. By "deeper", I mean that this vessel is involved with the internal organs-the heart in particular. Symptoms of chest pain, stomach pain, diarrhea, and abdominal masses can be treated with the Yin Wei. Remember, each organ system has a mental and emotional component as well, so this channel is often used to lift the spirits. A disturbance of the Yin Wei can lead to mental instability, low self esteem, and a lack of willpower. Interestingly, this channel is indicated for the treatment of heartbreak-it is said to help one recover from the traumas of a breakup.