Archeologists determined that Neolithic man, 8000 years ago used a primitive type of acupuncture tool called the bian-shi. It is a pyramidal shaped stone used to lance boils and stimulate certain points on the body to relieve pain. Later a sharp piece of bone was used for the same purpose and during the Shang Dynasty (1600 BC to 1100 BC), the metal acupuncture needle was invented. As they tracked their clinical results, they discovered acupoints with similar functions formed a line on the body and the sensation of the de - Qi would follow a certain pathway...a meridian or Jing-Luo.
There are 12 paired regular channels that relate to the organs and 8 extraordinary channels, 2 of which follow the midline. The Governing vessel on the dorsal midline and Conception vessel on the ventral midline. There are also collateral and divergent channels that are smaller branches of the major meridians that link the organs and meridians to one and other to form an intricately connected pathway throughout the body.
I use 3 kinds of acupuncture in my practice : dry needle, electro and aqua acupuncture. Dry needle is simple insertion of small acupuncture needles. During electro acupuncture, the needles are connected to a battery powered stimulator to deliver a painless low voltage current to the meridian. For Aqua acupuncture, I inject a small volume of vit b 12 or glucosamine into the point. This causes a small blister and gives continual stimulation over a few days.