The Yin and the Yang Linking Vessels connect all channels of the Qi they dominate in order to balance the Excess. Although their paths are similar, they are separate because the Yang governs the exterior of the body and links the Yang channels, while the Yin governs the interior and links the Yin channels. Common pathology includes epilepsy, Bi Syndrome, and loss of voice.
The Yang Linking Vessel flows through the channel of the Gallbladder on the side of the body, until it reaches the head. On the other hand, the Yin Linking Vessel starts from the inner lower leg where the Yin channels connect, and reaches the throat through the front of the body.
The Governing Vessel controls the Yang channels, while the Yang Stepping Vessel absorbs the Qi from the Yang channels. The Yang Linking Vessel connects them through its path. The Directing Vessel controls the Yin channels, while the Yin Stepping Vessel absorbs Qi from the Yin channels. The Yin Linking Vessel connects them.
Nutritive and Defensive Qi
The Yang Linking Vessel is in control of the Defensive Qi between the skin and muscles. The right state of the skin incites resistance to external pathological conditions. In a Full state, the Yang Linking Vessel incites fevers because the skin becomes too tight. In weak conditions, the Yang Linking Vessel weakens the defenses because the skin is loose.
The Yin Linking Vessel is in control of the Nutritive Qi and distributes it to the Yin organs. The Defensive Qi relies on the Nutritive Qi so they must remain in harmony. When the Nutritive Qi lacks within the Defensive Qi, the space between the Skin and muscles become unstable which manifests as impulsive sweating. The point Gui Zhi Tang Ramulus Cinnamomi Decoction is used to treat this disharmony.
Another manifestation of disharmony is minor sweating at the beginning of Wind invasions, and chronic Winds including muscle aches and stiffness. The points Du-16 Fengfu and G.B.-20 Fengchi are used to treat both types of pathology in the Yang Linking Vessel.
Mental and Emotional
Mental instability is due to the disharmony of the Linking Vessels; either the Yang is deficient and the Yin is in excess or the opposite. The disharmony may also cause depressive thoughts and lack of self control. Heart pains and depression become apparent when the interior of the body experiences pathogenic factors.
The Yin Linking Vessel is used when the Body is Blood and Yin deficient. The points used to treat depression are Ren-15 Jiuwei, Du-20 Baihui, ST-36 Zusanli and KI-9 Zhubin. The points used to treat anxiety include P-6 Neiguan, SP-4 Gongsun, Ren-15 Jiuwei, DU-24 Shenting, L.I.-4 Hegu, LIV-3 Taichong and KI-9 Zhubin.
The Yang Linking Vessel connects Yang channels in the head, so in pathology, there is an alternating sensation of hot and cold. This includes light and alternating fevers. The Yin Linking Vessel connects three Yin channels at the chest causing chest pains as a sign of pathology.