Researches on the development of the spinal cord in man, mammalia, and birds / by J. Lockhart Clarke.
- Jacob Augustus Lockhart Clarke
- Date:
- 1863
Licence: Public Domain Mark
Credit: Researches on the development of the spinal cord in man, mammalia, and birds / by J. Lockhart Clarke. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
5/38 page 913
![The anterior grey substance (/, fig. 1) was of a somewhat triangular form, with one of its angles behind and the other two in front. The posterior angle, which projected a little into the lateral part of the antero-lateral column, consisted of a very distinct and dark group of nuclei, and was separated from the posterior grey substance {b') by a much paler structure, composed chiefly of longitudinal and radiating fibres, which formed the rudiments of the lateral column. The anterior and outer angle was more obtuse (like a right angle rounded ofi), and consisted also of a distinct and dark, but larger group of nuclei, from Avhich the majority of the anterior nerve-roots [g) originated, and then proceeded outward and forward, to join the posterior roots which escaped in the same direction from the intervertebral ganglion. At its inner side, the triangular mass, like the posterior grey substance, was continuous with the layer surrounding the central canal by a nucleated network of the same kind. Throughout the whole of the ])osterior grey substance there was no diversity in the appearance either of the nuclei or of the close network of fibres by which they were connected. In the anterior grey substance, however, there was a slight diversity in the appearance of both. The nuclei contained in the separate groups already described were not larger, but they were less round or oval, or more irregular in shape, than those of any other part of the section, either anterior or posterior. They had also some tendency to aggregate into small, irregular and imperfectly isolated clusters, which were interspersed with granules and united by a looser and also irregular network, so that the entire structure had more or less the appearance of a sponge-like arrangement. In the central layer surrounding the canal, and of which the inner portion constitutes the epithelium, the nucleated network had a radiating tendency, which decreased on extending outward. In the parts between the separate groups or masses of grey sub- stance, the nuclei were densely but uniformly aggregated, and the network of fibres was less distinct. The antero-lateral white columns {h) were very small in proportion to the quantity of grey substance. Behind, where they joined the posterior columns, they were much shallower, and reduced, indeed, to a mere fringe on each side, sunk in the depression between the anterior and posterior grey substance, from which they were developed as the rudiments of the so-called lateral column. Hitherto the anterior median fissure had no existence, but fibres proceeding from the anterior nerve-roots on each side could be seen to cross each other transversely in front of the epithehal layer which surrounded the canal. These transverse fibres were the rudiments of the anterior commissure. Surrounding the white columns and enclosing the intervertebral ganglia, there was a quantity of loose tissue, which in front formed a deep layer (^), connecting the cord with the body of the vertebra {jj), and consisting of a nucleated network, the meshes of which were transversely extended. The nuclei of this network, although much less numerous than those of the grey substance of the cord, difiered from them but little in general appearance. Theu* connecting fibres, however, were thicker, coarser, less granular, and directly continuous, at the surface of the anterior commissure, with 6 I 2](https://iiif.wellcomecollection.org/image/b21456550_0005.jp2/full/800%2C/0/default.jpg)
