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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    knee, ankle and toes, with lateral flexion of the side and rumbling of the bowels, though it depended on the position of the electrode and the strength of stimulus whether only a part or the whole of these movements resulted. Starting above the upper limit of representation, say at the 10th dorsal segment, and then working downwards, the first movement obtained is lateral flexion of the side. The animal moves as if he had suddenly been poked in the side, the flexion of the spine being towards the side stimulated. The first movement observed in the muscles of the hip was always flexion and ne^ er extension, though adduction is not infrequently added, and occasionally rotation of the hip. This movement of the hip can be obtained on stimulating the posterior external column anywhere from the level of the 13th dorsal segment of the spinal cord, as low as the attachment of the 6th lumbar nerve. The area, stimulation of which causes flexion of the toes, extends from the 2nd lumbar segment to the upper part of the 7th lumbar segment, and the area similarly for flexion of the knee commences about half a segment lower. Rumbling in the intestine was produced occasionally hy stimulation of a point, or points in the postero-external column at about the level of the 5th or 6th lumbar segment, and the similar area for causing movement in the perinaeum and closure and protrusion of the anus was a little more extensive and a little lower down, whilst stimulating at any level from the 3rd lumbar to the 3rd sacral produced movement in the tail. An interesting point in connection with the latter was, that according to the position of application of the (minimal) stimulus did the base, the middle portion, or the tip of the tail move, the higher in the cord the point stimulated, the nearer to the base of the tail was the portion of tail which moved, but if the stimulus was a strong one, the whole of the tail moved. The chief movement occurred to the side in which the posterior external column had been stimulated, except occasionally in the lower part of the cord where the column of Goll was practically or entirely absent. Stimulation in the middle line caused, usually, depression of the tail, though occasionally elevation of the tail occurred, but the more laterally was the stimulus placed on the posterior external column, the more did the tail move to that side. Similarly with regard to the lateral extent of the areas mentioned above, whereas of course a strong stimulus caused movement in all the parts named, nevertheless in each case it was quite definite that the area for the tail was nearer the middle line than that for the hamstrings, the area for the hamstrings nearer the middle line than that for flexion of the hip, and this median of that area stimulation of which caused lateral flexion of the side. That the posterior fibres as they ascend in the cord are placed nearer the middle line than those entering the cord higher up, and so on, of course, is now well known anatomically, but the arrangement has not hitherto been demonstrated functionally, nor the fact that stimulation of certain paths or areas in the posterior external column gives definite movements in definite parts. These areas seem quite constant, and, of course, overlap one another in their vertical, if not in their lateral extent. That this is so would, of course, be anticipated from consideration of 2 D MDCCCXCVII.—B.