Myelin sheath (Myelin Sheath) is a membrane wrapped around the axon of nerve cells, that is, myelin sheath consists of myelin cells and cell membranes, is the plasma membrane of the nerve membrane cells along the axis of the axon of the helical winding formation of multilayered lipid bilayer structure, myelin sheath on the Langfei's node, which can make nerve impulses jumping transmission, myelin sheath staining in the pathologic diagnosis of a certain significance, myelin sheath pathological changes are divided into the early, intermediate and The pathological changes of myelin are categorized into early, middle and late stages. In the early stage, the coloring is deeper; in the middle stage of the lesion, myelin degenerates to form lipid droplets, which can be shown by lipid staining, and in the late stage, it completely collapses and is cleared by phagocytes, so there is no longer a positive result of myelin.

Myelin staining solution (Reichhorn red G method) utilizes a combination of Reichhorn red G and Brilliant green, in which Reichhorn red stains nerve myelin with red and Brilliant green stains axons, nerve bundles, etc. with green.