The Kidney Main Channel is the Yin channel associated with Water Element (水 shuǐ). Known as the ‘Minister of Power’, the kidney is regarded as the body’s most important reservoir of essential energy. The original prenatal energy (yuan qi) which forms the basis of life is stored in the kidney organ-energy system. This is why the kidneys are also known as the ‘Root of Life’. In the Chinese view, the kidney organ system also includes the adrenal glands, which consist of the adrenal medulla and the adrenal cortex. These glands sit like hats on top of the kidneys and secrete a wide range of essential hormones that regulate metabolism, excretion, immunity, sexual potency and fertility. Destruction of the adrenal cortex is fatal. The kidney system also includes what the Chinese call the ‘external kidneys’: the testicles in men and the ovaries in women. Thus, the kidneys control sexual and reproductive functions and provide the body’s prime source of sexual vitality, which the Chinese regard as a major indicator of health and immunity. The kidneys themselves are responsible for filtering waste metabolites from the blood and moving them onwards to the bladder for excretion in urine. Along with the large intestine, the kidneys control the balance of fluids in the body. In addition, they regulate the body’s acid-alkaline balance (pH) by selectively filtering out or retaining various minerals. The kidneys control the growth and development of bones and nourish the marrow, which is the body’s source of red and white blood cells. Weak kidney energy is therefore a prime cause of anemia and immune deficiency. The Chinese view the spinal cord and the brain as forms of marrow, and therefore poor memory, inability to think clearly, and backache are all regarded as indicators of impaired kidney function and deficient kidney energy.
- The Kidney primary channel begins under the little toe, which is reached by a branch separating from the BL (Bladder Channel – Zu Tai Yang) at its endpoint at BL 67 (Reaching Yin) (zhiyin).
- The Kidney primary channel diagonally crosses the sole of the foot to KI 01 (Gushing Spring) (yongquan) and to KI 02 (Blazing Valley) (rangu) below the navicular tuberosity
- continues to the posterior aspect of the medial malleolus and descends to enter the heel.
- From here it ascends the medial aspect of the lower leg, intersecting with SP 06 (Three Yin Intersection) (yinlingquan) and continuing to ascend the posteromedial aspect of the thigh towards the perineum where it divides into two branches:
- the deep, internal branch travels to GV 01 (Long Strong) (changqiang) and ascends alongside the spine to connect with its pertaining zang-Organ, the Kidneys (shen), and its paired fu-Organ, the Bladder (pangguang). Here it divides into smaller branches which connect with CV 04 (Gate of the Source) (guanyuan) and CV 03 (Middle Pole) (zhongji), and, according to some authors, also with CV 07 (Yin Intersection) (yinjiao).
- From the Kidney (shen) a branch ascends to the Liver (gan), runs to and spreads in the Lung (fei), continues to the trachea and terminates at the root of the tongue.
- From the Lung (fei), an inner branch travels to the Heart (xin), where it meets the PC (Pericardium Channel – Shou Jue Yin) (deep Yin–Yin connection). It then disperses in the chest and reaches CV 17 (Chest Centre) (shanzhong).
- the external branch separates in the perineal region and runs to the lower abdomen at KI 11 (Pubic Bone) (henggu). From the pubic bone it ascends initially 0.5 cun lateral to the anterior midline, from the 5th intercostal space (KI 22 (Walking Corridor)) 2 cun lateral to the midline to the infraclavicular fossa where it ends in KI 27 (Shu Mansion) (shufu).
The main functions of Kidney are:
- It stores the Jing (ancestral energy);
- It is the root of the Yin and Yang;
- It dominates water metabolism;
- It allows the collection of Qi;
- It dominates the bones and produces the marrow that fills the brain;
- It opens in the ears;
- It manifests in the hair;
- It governs the lower orifices;
- It is the residence of the Zhi (will);
- It is in relation with Ming Men (GV 04 (Gate of Life)).