On out-lying nerve-cells in the mammalian spinal-cord / by C.S. Sherrington ; communicated by M. Foster.

  • Sherrington, Charles Scott, Sir, 1857-1952.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: On out-lying nerve-cells in the mammalian spinal-cord / by C.S. Sherrington ; communicated by M. Foster. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Out-lyin(j Ganghon-CeVs in the Posterior Column. As in the ajitero-lateral, so also in the posterior column of the cord out-ljdng gang- lion-cells exist. And it would seem that the anatomy of the out-lying cells in the posterior column is less complex than that of the former classes. In the first place, the cells appear to be confined to one portion of the posterior column, namely, the extero-posterior division of it, and in that division to one particular area, namely, the radicular zone. In the second place, one has obtained definite evidence of their existence from a certain region only of the length of the cord, namely, from that which is especially characterised by the large dimensions assumed by the posterior vesicular column of Clarke, The out-lying cells ap[iear to be situated in the root-zone exclusively upon certain of the horizontal radiations of the root-fibres from the white column into the grey cornu. These radiations are among those which in transverse sections through the cord can be seen to ])ass from the dorso-median limit of the root-zone in a ventral and lateral direction to enter the grey substance in the neighbourhood of Clarke’s column, often describing as they do so bold curves with the convexity turned toward the postero- median fissure. They are radiations consisting of root-fibres, Avhich belong to the median division in Krause’s^ classification of the bundles of the dorsal roots. They enter the g)-ey matter without previously passing through any part of the mesial limb of the gelatinous substance. IjEciiTEREwt has shown that they are composed of fibres which already are possessed of the medullary sheath in the human fcetus of 25 cm. length, and are therefore ainong the earliest of the fibres of the cord to be developed. It is also to 1)6 rememl)ered that their fibres are among those of largest calibre in the whole of the dorsal spinal nei've-root. 1 he form of the out-lying cells found in these radiations of the dorsal root may^be described as oval (figs. G, 7, 8, Plate 4) ; one end is usually con.siderably the less pointed. A nucleus, which is large and coiitains a very obvious nucleolus, is fairly cen- trally placed within tlie cell, though often somewhat nearer the blunter of the two extremities, 'fhe cells have not been observed isolated in teased preparations, but they may really he of a more symmetrically bipolar figure than the foregoing descrip- tion would suggest. Although they are certainly chiefly extended in the plane at right angles to the long axis of the cord, a very slight inclination in such a }>lane, either of themselves or of the section in which they lie, would suffice to truncate one end of the s])indle-sha])ed cell-body. In such a. case the nucleus, if centrally placed, would appear neai'er to the moi'e j'ounded pole. That tins does actually hap})en and frec^ueiitly ex])lains the somewhat unipolar appearance of the cell, is suggested by the fact that the more j)ointed end, continued into an obvious cell-process, is sojnetimes turned with the fibres of the dorsal I’oot in the direction of the grey sul)stance of the * ‘ AIlgeiiK'iiu' 11. Mikroskop. Aiiatoiiiie,’ 187G, p. t ‘ .\i-cliiv f. ,\nal. n. Physiol,, .Anal. Alilli,,’ 1887, p. I2G.