The value of nerve-supply in the determination of muscular homologies and anomalies / by D. J. Cunningham.

  • Daniel John Cunningham
Date:
[1890?]
Catalogue details

Licence: Public Domain Mark

Credit: The value of nerve-supply in the determination of muscular homologies and anomalies / by D. J. Cunningham. 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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    division of the 5th nerve.i Many other instances might be given, but those that I have quoted are sufficient to show, what indeed is a matter of common knowledge to every teacher of anatomy, viz., that nerve-fibres outside the spinal cord do not in every case follow the same paths as they travel towards their different destinations. Both muscles and the nerves which are associated with them are arranged in groups, and it is where these come into contact with each other that there is a tendency exhibited for one or other of the nerves to overstep the boundary line and extend its territory at the expense of its neighbour. In dealing with this question on a former occasion, I chose the intrinsic muscles of the foot and the two plantar nerves for the purpose of testing the value of nerve-supply in the deter- mination of muscle homologies. No better ground could be found, because here we have a series of muscles which are easily and readily identified. We may fairly assume that the muscles attached to any particular digit are homologous with the muscles connected with the corresponding digit in all animals. Amongst the large number of different mammals which I examined, I only encountered four in which there was a decided deviation from the ordinary typical distribution of the plantar nerves. In three of these, viz., the Elephant, Hyrax, and Beaver, the internal plantar nerve invades the territory of the external plantar and seizes upon muscles which usually do not belong to it. The Fox-bat affords an example of the opposite kind; the external plantar lays hold upon a muscle which in the typical condition is under the sway of the internal plantar. I need not enter further into particulars, but I may be allowed to mention that, by the appearances presented, I was led to consider that the muscular distribution of the internal plantar nerve has in all probability been more extensive at one time than it is now. It is possible that at one time the two plantar nerves took an equal share in the intrinsic muscle supply of the foot. The hand and foot of the Hyrax present a condition which approaches very nearly to this. Judging from the arrangement in the Fox- bat, there appears to be a tendency for the external plantar nerve to drive the internal plantar nerve out of the field altogether. > Proc. Roy. Hoc. L<mdon, 1868, p. 456, and Jow. Anat. and Phys., Nov. 1866.
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