Volume 1
Quain's elements of anatomy / edited by Edward Albert Schäfer and George Dancer Thane.
- Date:
- 1895-1898
Licence: Public Domain Mark
Credit: Quain's elements of anatomy / edited by Edward Albert Schäfer and George Dancer Thane. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
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![mesial group : on this account it is thought to give origin to the nerves which supply the dorsal muscles of the spinal column. It is sometimes described as forming two sub-groups, viz. : a dorso-mesial and a ventro-mesial. The ventro-lateral gi'oup probably' gives origin to the nerves which supply the lateral and venEfal muscles of the trunk, including the muscles of respiration. In tEe^ervical region it is described as consisting of two parts, one more laterally sitiiated, which gives originJbo fibres of the spinal accessory, and another,^ofe mesially placed, which'is believed to grve'6flf''th^ fil3T5S~15fthe phrenic nerve. In tBe~]umbar enlargement it also tends to be sub-divided. ~ The dorso-lateral group is mainly developed in the cervical enlargement and lumbar enlargement, and has an eTidenlE'relationship to th'e~n5FTe-roots of tEe brachi'ar'a'nS sacral plexuses. It also shows subordinate groupings, which probably have special connections with particular groups of the limb-muscles. For various conjectures regarding both these and other cell-groupings in the grey matter, the reader may consult the paper by Kaiser, which is given in the Bibliography. Some of the cells which are nearer the anterior commissure send their axis- cylinder processes through this commissure to the anterior white column of the other half of the cord : it is believed that these processes may be connected with nerve-fibres of the corresponding anterior root of the other side. In some of the lower vertebrates it may be made out that there are variations in the size of the column of cells of the anterior horn in successive portions of the cord, the cells being more numerous opposite the points of entrance of tte nerve-roots, the attachment of which to the cord is in them more localized than in man and higher vertebrates. In this way some- what of a segmental formation of the column is indicated, and in some fishes and reptiles the enlargement of the group of cells and its enclosing grey matter is sufficiently marked to produce an external swelling opposite each nerve-pair. A similar segmentation is indicated in an early stage of development in all vertebrates, including man, by the fact that the cord is somewhat enlarged opposite each pair of nerve-roots. Clarke's column.—A second very well marked group or column of large cells, which occupies in transverse section an area at the inner or mesial angle of the base of the posterior horn (fig. 14,/), and appears cut off from the rest of the grey matter by a curved bundle of fibres derived from the posterior root, extends along the middle region of the cord from about the third lumbar to the seventh cervical* nerve. This was termed by Lockhart Clarke the posterior vesicular column; if'is usually known as Clarke^s^column, although the cells were first noticed by Stilling. It is best developed in the lower part of the dorsal (thoracic) region. From the fact that it is almost entirely confined to the thoracic region of the cord it was termed by Stilling the dorsal nucleus. But although ceasing above and below the points mentioned, it is not altogether unrepresented in other parts, for groups of cells are found in a similar situation opposite the origin of the second and third sacral nerves ( sacral nucleus of Stilling) and opposite the origin of the third and^ourth cervical nerves ( cervical nucleus); and elsewhere there are scattered cells of the same character in the same part of the section of the cord. The cells of this column, like most, if not all, the cells of the spinal cord, are multipolar, and their axis-cylinder processes tend towards the lateral column, where they are believed to form the direct cerebellar tracb (Flcchsig). The cells themselves are surrounded by a fine plexus of nerve-fibrils, probably derived from collaterals of the posterior root-fibres. They are of large size, measuring, according to Mott, in their longest diameter, which is directed longitudinally, from 40/Lt to 90/i, the largest being found in the lowermost part of the column. In the fatus and even in the new-born child they_are_much smaller (25/i to 30yu), but by'the second or third year after birth they have nearly attained the same size as in the adult. Lateral cell-column.—A third column of cells lies in the intermedio-lateral](https://iiif.wellcomecollection.org/image/b21294021_0001_0024.jp2/full/800%2C/0/default.jpg)
