There are eight different Extraordinary Vessels and they connect the Six Extraordinary Yang Organs (Uterus, Brain, Marrow, Bones, Blood Vessels and Gallbladder) with the other Organs. For example, the Uterus connects to the Kidneys through the Directing and Penetrating Vessels.
These Extraordinary Vessels are like reservoirs of energy, as opposed to the main Channels which are like rivers. They connect to Channels and balance Yin and Yang flow between them. In effect, Channels can "tap into" the Extraordinary Vessels reserves or store Yin and Yang in them, depending on the needs.
The Governing (Du Mai 督脉), Directing (Ren Mai 任脉) and Penetrating (Chong Mai 冲脉) Vessels are the most important of the eight Vessels because they are the origin of all. Each of the three start directly from the space between both Kidneys because their main task is to supply and circulate Kidney Essence. They can be seen as the three branches of the same Vessel originating from the Kidneys and then taking different pathways. Compared with the other Extraordinary Vessels, these three can be used in clinical practice to influence a patient’s status at a deep fundamental level.
The Governing Vessel originates in the space between the Kidneys and goes around the vagina for women or around penis for men. Then it flows to perineum, passes around buttocks and upper thighs, rises along the spine and arrives at the head vertex. Finally it goes down the forehead and ends at the space between nose and lips.
The Governing Vessel is called the 'Sea of Yang Channels' because it has impacts on all Yang Channels. It can be used to tonifies Kidney Yang in both men and women. It also strengthens the Spine and Brain because it connects these two Organs with the Kidneys and spreads Kidney Essence in the form of Marrow. Therefore, the Governing Vessel has a substantial influence over the Mind (Shen) because the Marrow is the base material that constitutes the Mind. As a result the Vessel can be used to calm the Mind, lift mood and improve memory.