Investigations into the segmental representation of movements in the lumbar region of the mammalian spinal cord : excitation of the spinal cord, and direct excitation of the spinal nerve roots / by W. Page May ; [communicated by Victor Horsley].

  • May, W. Page (William Page), 1863-1910.
Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: Investigations into the segmental representation of movements in the lumbar region of the mammalian spinal cord : excitation of the spinal cord, and direct excitation of the spinal nerve roots / by W. Page May ; [communicated by Victor Horsley]. 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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    the 5th posterior root, as before, now evolved only contraction in the back muscles and very slight flexion of the hip. The 5th anterior root was then divided, and stimulation of the 5th posterior lumbar root gave contraction in the back muscles as before, but no movement whatever in the lower limb. Of course, excitation of the 4th anterior lumbar root, on being stimulated directly, gave the ordinary result, viz., extension of the hip and knee, ankle, and toes, with spreading out of the- latter. By varying several other experiments of the same kind, precisely similar results were obtained. From the foregoing results obtained by the excitation method, it may be justly concluded that the normal relationship of any given posterior root (sensori-motor reflex) to the segments in the spinal cord is that the destination of its root-fibres is nerve centres in segments below the point of entry into the spinal cord. It now remains to see how far this generalisation is justified by other facts obtained in other ways. In the first place, the fact is of much interest that as long ago as 1847 Claude Bernakd found that the 6th and 7th posterior lumbar roots supplied the 7th anterior root. Another point in the same direction is the fact that if the lumbar region be cut across, then stimulation of the posterior external column, as high as the margin of the cut surface of the lower portion, will give as intense a movement as before section. Finally, the fact that all observers are agreed that, by the method of excitation of the anterior roots, the highest segment in the spinal cord from which movements have been elicited in the lower limb is the second. The experiments in the present investigation show that excitation of the cord as high as the 13th dorsal posterior segment evokes movements in the lower limb. This apparent discrepancy is, it will be seen, a proof of the position just advanced, since it shows that the uppermost nerve centre containing motor representation of the lower limb received afferent impulses by means of the posterior root, which is two or three segments higher (nearer the cerebrum). Evidence of a like kind is afforded by anatomical researches. In the first place, Schultze found that after damage to the cervical enlargement a comma-shaped area of descending degeneration occurred in the posterior columns. Baebacci found also after a transverse lesion of the cord that scattered descending degeneration could be found throughout the whole breadth of the posterior column. The most important anatomical fact, however, is the well-known discovery by Kamon-y-Cajal, confirmed by Kolliker, Eetzius, and Golgi, that the posterior root fibres divide almost immediately upon their entrance into the cord into two main branches, one ascending and one descending. I venture to provisionally suggest that the ascending branch is, perhaps, chiefly concerned with sensory (^.6., cerebral) impulses, and the lower branch with local sensori-motor reflex actions. It has also been shown in the horse that there is a difference in level between the 2 E MDCCCXCVIT.—B.