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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    to the same side). ' But of the facts observed the chief was the very local effect which would be obtained by varying the point stimulated. Thus stimulation of a point 1 millim. centrally or laterally of a given point often produced an entirely different resulting movement, or no response at all, which fact is clearly of much importance in showing that with the above strength of current the restriction of the stimulus to one point must be sufficiently well obtained. 1 2. Mechanical. , As a means of controlling the observations derived from electrical excitation, mechanical stimulation was sometimes employed in examining the nerve roots, and was evoked by pinching the tissues with fine forceps. I’he results obtained were precisely the same. ^ The results obtained by direct excitation of the cord will now be grouped as follows :— (1.) Gross localisation according to the general structure of the cord. (2.) Minute localisation within the excitable area. ... ’ .: Results Obtained by Direct Excitation of the Spinal Cord (Dog). ^: ! Gross Localisation. (a.) Area Excitable. The excitable area of the surface of the cord itself is the postero-external column. Stimulation of the column of Goll as a rule produced no movement except in the lower lumbar region, where that column is either very narrow or entirely absent. Thus at about the level of the 7th lumbar nerve stimulation of the posterior column in the middle line produced movement, namely flexion of the hip, flexion of the ankle, and flexion of the toes. It is probable that the effect is here due to the stimulus directly spreading to the fibres of the postero-external column owing to the narrowness of the intervening portion of Gold’s column. As already observed, excitation of the antero-lateral column with any stimulus less than thrice that adequate for the posterior columns was without result. It seems, therefore, proper to conclude that the postero- external column can alone be considered for the purposes of minute localisation as excitable on its surface as compared with the other column of the cord. The reason for this probably is, that the postero-external columns are made up almost entirely of the branches (ascending, descending, and collateral) of the posterior roots, and that these are at and near the surface of the cord. (b.) Unilaterality. ■ ^ i : In the large majority (91*5 per cent.) of experiments on animals, the fact was 2 c 2