Electron Microscopy of Human Spinal-Nerve Roots

Two SPECIMENS of human dorsal nerve root have been obtained, sufficiently fresh for electron microscopy. They have, respectively, some of the characteristics of normal and long-damaged dorsal roots as seen in the rat,¹but they also exhibit features not seen in rat material, which, taken with the rarity of the material, make the findings of some interest. Material and Methods The tissues were small pieces of a fourth lumbar dorsal nerve root and of a sixth cervical dorsal nerve rootlet, obtained at operation when they were fixed for three hours in buffered 1% osmium tetroxide and then stained for three hours in 1% phosphotungstic acid during the dehydration which led to embedding in Araldite. Sections were cut on Porter-Blum and Huxley ultramicrotomes, mounted upon unfilmed copper grids, and examined in an Elmiskop I electron microscope. The lumbar root was obtained from a patient who had presented with slow