Nei Jing is thousands of years old, yet here is an astounding description of fetal development that includes aspects of eastern medicine, specifically the meridians.
The meridians are the foundation of the body. This importance is poetically described by Huang Di himself in the beginning of Ling Shu, chapter ten. The young doctor Lei Gong begins the discussion when he asks the following question;
“[Ling Shu, chapter forty-eight, entitled] ‘Jin Fu’ states, every acupuncture theory begins with the meridians, [they] circulate the nutrients, traverse and regulate every measure of the body, internally can treat the five zang organs, and the external fu organs. I wish for you to thoroughly explain this to me.” Huang Di replies, “[When] human life begins, first there is the combination of the essence [of both parents], the essence becomes the brain marrow, the bones form, the vessels begin to deliver nutrition, the sinews begin attaching, the muscles form like walls, the skin solidifies and the hair develops, food then enters the stomach, the meridians are able to go through, transporting blood and qi.” Lei Gong asks, “Can this lowly servant hear about the meridian’s origins?” Huang Di answers, “The doctor [that knows] the meridians, can determine if the patient will live or die, they can tell which of the many diseases the patients has, they can regulate deficiency and excess [conditions], and tell if the meridians are flowing properly.”
The meridians are distributed throughout the body. Every part of the body is connected through the meridian system, from the innermost organ, to the outer surface of the skin. The doctor, by using the needle to pierce the skin to reach the acupuncture points of the meridian, is then able to touch the associated organ at the same time. This is how acupuncture is able to treat minor aches and pains, Re Bing, as well as any internal medical disease.