The purpose of this review is to describe the methodology, instruments, and subject animals used until now for studies of the meridian (Kyungrak) system and the primo vascular system (PVS). The PVS is observed as an anatomical system distributed in cavities, organs, and tissues throughout the body. We analyzed the most important points of the PVS based on the results obtained until the present. Our main effort has been directed to describing the main thesis relating to the morphological structures and their topography, the functional mechanisms of the PVS, and possible roles of the PVS in pathological processes. The substance of the PVS in all its aspects is as a system covering the whole body and regulating and coordinating the biological processes that are the basis for life. In conclusion, we suggest that the finding of the PVS represents the discovery of a new integrated morphological-functional system.