Yin and yang are fundamental concepts in the oriental view of the world. Everything manifests through an interplay of opposites: yin and yang. Everything has yin and yang qualities within them, but the balance between yin and yang varies.
- Yang qualities include expansiveness, dryness, masculinity, lightness, heat and hollowness.
- Yin qualities include femininity, receptivity, darkness, coolness and solidity.
Each meridian is seen to be predominantly yin or predominantly yang. Each yang meridian needs its paired yin meridian for its completion. Each yin meridian needs to be balanced by its paired yang meridian. Each meridian flows in a particular direction. In general yin meridians flow from the feet towards the head, and yang meridians flow from the head to the feet. Each pair is also linked to an element, except for the fire element which has four meridians associated with it:
- Wood: Yin: LR (Liver Channel – Zu Jue Yin); Yang: GB (Gallbladder Meridian – Zu Shao Yang).
- Fire (Imperial Fire): Yin: HT (Heart Channel – Shou Shao Yin); Yang: SI (Small Intestine Channel – Shou Tai Yang).
- Fire (Ministerial Fire): Yin: PC (Pericardium Channel – Shou Jue Yin); Yang: TH (Triple Heater Channel – Shou Shao Yang).
- Earth: Yin: SP (Spleen Channel – Zu Tai Yin); Yang: ST (Stomach Channel – Zu Yang Ming).
- Metal: Yin: LU (Lung Channel – Shou Tai Yin); Yang: LI (Large Intestine Channel – Shou Yang Ming).
- Water: Yin: KI (Kidney Channel – Zu Shao Yin); Yang: BL (Bladder Channel – Zu Tai Yang).
Some kinesiology systems focus on the traditional five elements (see also 5 Elements Theory and Chinese Medicine Elements), but others, such as Applied Physiology and Health Kinesiology also include the central and governing meridians and treat these as a separate element (see also 7 Elements Theory).