NEW RESULTS IN VISUALIZATION OF THE DURA- MATER-SPINALIS BY SCANNING ELECTRON-MICROSCOPY

Although there are various published descriptions of the dura mater sp inalis [4, 7, 9, 11, 16], some points relating to the texture of the c ollagen fibres in the dura have still not been adequately explained. l n this study the orientation of the collagen fibril bundles was reveal ed with the aid of scanning electron microscopy, and our observations have yielded new insights into the three-dimensional structure of the human dura mater spinalis. Materials and methods. The preparations use d were taken from the bodies of four persons who had died of acute car diac infarct at the ages of 70-78 years. The histories of these patien ts gave no indications of earlier neurological, endocrine or septic il lnesses. The tissue examined was taken 8-12 h after death in all cases ; it was immediately fixed in glutaraldehyde and then processed for sc anning electron microscopy in the usual way. Results. ln the outermost (epidural) layer of the dura mater spinalis the collagen fibres are b unched together in bands that run in all directions. Elastic fibres 2 mm thick are woven into this three-dimensional network of collagen sys tems. On the inside (the arachnoid side) thin collagen fibres are fuse d into layers in such a way that the innermost layer resting on the ar achnoid has a smooth,shiny appearance comparable to that of a serosa. lt is attached to the actual dura with a supporting ba nd of connectiv e tissue. Rests of the subdural neuroepithelium could contribute to th e smooth appearance of the superficial aspect. Conclusions. The outerm ost layer of the dura is made up mainly of collegen fibres, which run in all three directions-longitudinal,horizontal and transverse-both si ngly and in groups. These findings are at odds with ''classic'' descri ptions, according to which the fibres in the dura mater spinalis all h ave a parallel course with a longitudinal orientation in tangential se ctions.