Resin Embedding (Plastics)
Standard paraffin embedded, H&E stained sections of nerves simply do not provide adequate detail to allow for a complete examination. This is well illustrated in the images on this page.
The upper left image is a standard paraffin embedded, H&E stained cross-section of nerve; detail is lacking. The lower left image is a cross-section of nerve embedded in soft plastic (in this case, GMA). Without osmium fixation there is little, if any, advantage of this technique over standard paraffin.
The images on the right show the benefit of osmium post-fixation. The lower right image is from a well-fixed, osmicated, paraffin embedded H&E stained nerve cross-section. Note the myelin sheaths are readily visible.
The upper right image is the best way for nerves to be examined. A nerve cross-section is fixed in osmium, embedded in resin, sectioned very thin (for enhanced detail), and stained with toluidine blue. Note the superb detail which allows for a thorough examination of the nerve.
See our page on nerve morphometry for an example of the benefits of using proper nerve preparation.