Defining Meridians: a Modern Basis of Understanding

Acupuncture, one of the primary methods of treatment in traditional Oriental medicine, is based on a system of meridians. Along the meridians lie acupuncture points or acupoints, which are stimulated by needling, pressure or heat to resolve a clinical problem. A number of methods have been used to identify meridians and to explain them anatomically. Thus, tendinomuscular structures, primo-vessels (Bonghan ducts), regions of increased temperature and low skin resistance have been suggested to represent meridians or as methods to identify them. However, none of these methods have met the criteria for a meridian, an entity that, when stimulated by acupuncture can result in clinical improvement. More recently, modern physiologists have put forward the "neural hypothesis" stating that the clinical influence of acupuncture is transmitted primarily through stimulation of sensory nerves that provide signals to the brain, which processes this information and then causes clinical changes associated with treatment. Although additional research is warranted to investigate the role of some of the structures identified, it seems clear that the peripheral and central nervous system can now be considered to be the most rational basis for defining meridians. The meridian maps and associated acupoints located along them are best viewed as road maps that can guide practitioners towards applying acupuncture to achieve optimal clinical results.