[Overview of researches on the underlying mechanism of that "Hegu (LI 4) is indicated for orofacial disorders"].

It has been well documented in Chinese acupuncture medicine that "Hegu (LI 4) is indicated for orofacial problems". In the present paper, the authors analyze their correlation from the learning of modern medicine and results of recent experimental studies instead of traditional meridian theory of acupuncturology. The afferent nerve fibers from the LI 4 region and the orofacial part ascend to the spinal cord, nucleus of solitary tract, reticular formation, thalamus and the cerebral cortex, respectively, and overlap in the thalamus, cerebral cortex, etc. Under the circumstances, the interaction and functional integration of the afferent signals from LI 4 acupoint and the orofacial region may occur in the central nervous system. In addition, many relevant neuroactive substances (for example, serotonin, substance P, enkephalin, y-aminobutyric acid, glycine, calcitonin gene-related peptide, etc.) released from the sensory and motor neurons in the corresponding cerebral regions may constitute part of the substantial basis of that "Hegu (LI 4) is indicated for many orofacial disorders".