The 12 meridians each have a place around the spherical meridian flow (SMF). There are pathways leading between the 12 meridians. Qi, life force, moves along these pathways passing through the expressions of each meridian.
As Qi passes through a meridian, the meridian is activated; it expresses. The spirit of that meridian expresses in the body. The Qi then continues flowing on to activate other meridians.
As Qi progresses through the meridians around the SMF, the body is healthy. Yin & Yang are balanced and coordinated.