采用中西医对照的方法研究经络的实质，认为中医学的经脉、营血、经筋、卫气和皮肤是经络实质。西医学的神经系统和循环系统是经络实质的主体；肌肉和皮肤属于经络实质次要部分。中医学的脉对应的是西医学的血管和淋巴管；中医学的经筋对应的是西医学的肌肉和神经；中医学的营血对应的是西医学的血液和淋巴液；中医学的皮肤是西医学的皮肤。卫气的功能至关重要，其功能与多种神经功能相仿，其位置又与神经血管相傍行一致。

In this article, we discuss the essence of meridians with the method of comparing traditional Chinese medicine (TCM) with western medicine. We consider that the channels (jingmai), nutrient-blood(yingxue), muscle channels (jingjin), defensive qi(weiqi), and skin(pifu)are the essence of meridians in TCM. The nervous system and circulatory system of western medicine are the main body of the meridians; the muscles and skin belong to the minor part of the meridians. The channels of TCM correspond to the blood vessels and lymphatic vessels of western medicine; the muscle channels of TCM correspond to the muscles and nerves of western medicine; the nutrient-blood of TCM corresponds to the blood and lymph fluid of western medicine; the skin of TCM is similar to the skin in western medicine. The function of defensive qi is very important, whose function and position are similar to those of many nerves.