The Relationship of the Kidney to other Organs
1) Dominating Bones and Teeth, Engendering Marrow to Fill up the Brain
Domination of the bones and engendering of marrow account for the function of the kidney essential qi to stimulate growth and development of the human body. TCM believes that the kidney stores essence, which engenders marrow. The marrow develops in the bone cavities and nourishes their growth and development. Hence, the kidney,
essence, marrow, and bones form a system which is inter-connected. If the kidneyessence is sufficient, the marrow is richly produced and the bones are nourished. Their growth will lead to solid and hard bones. Conversely, if the kidney-essence is insufficient, the bone marrow is lacking in source, and it fails to nourish the bones, giving rise to mal-development of bone, soft and weak bone, a late closure of the fontanel in children, weakness and soreness of the lumbar region and knees, difficulty walking, weakness or even atrophy of the feet in adults, fragile bones, and easily fractured bones in elderly people.
"Marrow" includes the bone marrow, spinal cord and brain. Bone marrow is stored
in the bone cavities; the spinal cord is located in the vertebral column; and the brain is situated in the cranial cavity. These three kinds of marrow are derived from the essential qi of the kidney. The prosperity or decline of the kidney essential qi has a great influence upon not only the growth and development of bones, but also the enrichment and development of the marrow. TCM believes that "the brain is the sea of marrow," because the spinal cord ascends to communicate with the brain, which is formed by the collection of marrow. If the kidney-essence is abundant, and "the sea of marrow" full, it will nourish the brain, and lead to full energy, clear thinking, acute hearing, good vision, and good memory. On the contrary, if the kidney-essence is insufficient, "the sea of marrow" lacking in enrichment, it will cause a mal-development of the brain, low intelligence, blockhead in children, poor memory, dull thinking, dizziness, blurred vision, tinnitus,insomnia, even amnesia in adults.
The teeth is a part of the bone, and there is a saying that "The teeth are the surplus of the bones. " Since teeth and bone share the same source, they are both nourished by the kidney essential qi. Abundance of the essence and marrow result in firm, strong and healthy teeth. If the essence and marrow are in deficiency, the teeth lack nourishment,resulting in looseness or loss of teeth. In treating these conditions, reinforcement of the kidney-essence is often ascribed as the principle treatment, for the patient responds with a heightened curative effect.
The theory of "the kidney dominates bones" has been further proved by experimental study. For example, some herbs for tonifying the kidney also act in strengthening tough and tensile degrees of the bones, and reinforcing the kidney is often used to treat fractures, and accelerate bone healing. In recent years according to this theory, many disorders of the bone have obtained a better curative effect through treatment of the kidney.
2) Manifestations in the Hair
In this context, "hair" refers to the hair on the head. The general condition of the kidney essential qi is reflected in the hair. Thus Chapter 10 in the Plain Questions states: "The kidney dominates bones, and its health manifests in the hair. " The growth and loss of hair, or loss of its luster forming a withered state are all associated with the strength of the kidney essential qi. It is also reliant on the nourishing action of the blood, and is known as "the surplus of blood. " However, the mechanism of hair originates from the kidney, for it is the kidney that stores the essence which manufactures the blood to nourish the hair. The changes between luster and withered, black or white, depend on the prosperity and decline of the kidney essential qi. In childhood,the kidney essential qi develops,and hair grows longer and fastor. During youth and in the prime of life, the kidney essential qi flourishes, the hair is lustrous and jet-black. In old age, the kidney essential
qi declines and the hair turns white, withers, and falls out. These are normal physiological conditions. The cases studied in clinical settings, are those due to impairment of the kidney essential qi, which results in an abnormal occurrence of the above conditions.
3) Opening into the Ears, External Genitalia and Anus
The openings of the kidney differs from those of the other four viscera. It had upper and lower openings, the former referring to the ears, and the latter to the external genitalia and anus.
The ears are audio-organs. The acuteness of hearing depends on the prosperity or decline of the kidney essential qi. Only when the qi is abundant, can hearing be acute, thus stated in Chapter 14 of the Spirit Pivot: "The kidney qi connects to the ears, and if the kidney essential qi is in harmony, the ear can perceive the five sounds. " Insufficiency of kidney essential qi may give rise to diminished hearing, tinnitus, or deafness. Dimin ished hearing and deafness of aged people are often caused by the physiological debilitation of the kidney essential qi.
"Two yins" includes the "anterior yin" and "posterior yin. " The "anterior yin"
refers to the urethra and genitalia which function in the discharge of urine and in reproduction. Although the discharging of urine is controlled by the urinary bladder, it is also reliant on the transformative function of the kidney-qi. Therefore, deficiency of the kid ney-qi may cause long micturition with clear and frequent urination, enuresis, incontinence of urine, oliguria anuria and dribbling urination. Deficiency of kidney-qi may also affect the function of the reproductive system, resulting in impotence, seminal emission, premature ejaculation, etc.
"Posterior yin" refers to the anus, which discharges the stools. Although its function is governed mainly by the large intestine and spleen, it is also reliant on the transformative and warming function of the kidney-qi Hence, disorder of the kidney often affects the discharge of stools. An example of this is that insufficiency of kidney-yin may cause constipation, and deficiency of kidney-yang can lead to diarrhea, and unconsolidation of kidney-qi may give rise to prolonged diarrhea and prolapse of rectum.
