On the descending degenerations which follow lesions of the gyrus marginalis and gyrus fornicatus in monkeys / by E.P. France ; with an introduction by Professor Schäfer.

  • France, E.P.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: On the descending degenerations which follow lesions of the gyrus marginalis and gyrus fornicatus in monkeys / by E.P. France ; with an introduction by Professor Schäfer. 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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    other side, but very much less in amount. This degeneration has been followed down the cord as far as the lumbar region in some instances. The shape of the degeneration in the lateral column is sufficiently constant in all cases where there has been considerable injury to the marginal convolution for it to be considered characteristic of this lesion. In the cervical region it is narrowly triangular or claw-shaped, the base being towards the posterior cornu, and the (expanded) apex at the surface of the cord, reaching this at about the middle of the lateral border (see fig. Ic.). One side of the triangle is formed by the line of separation between the crossed pyramidal tract and the direct cerebellar tract. Along this line the degeneration always appears to be most complete, that is to say, the degeneration is chiefly confined to the posterior and outer part of the crossed pyramidal tract; this is noticeable down the whole of the cord. In the cervical region the degeneration spreads out immediately within the circumference of the cord, the direct cerebellar tract appearing as if pushed backwards towards the apex of the posterior cornu, where it occupies an area which is triangular in section, in place of the oblong tract seen in sections lower down. In the upper dorsal region the appearance is much the same as in the cervical region, except that the connection of the degeneration with the circumference of the cord is becoming less extensive, although the whole tract of degeneration has approached a little nearer the circumference, from which it is separated by the now oblong cerebellar tract. In the lower dorsal region the degenerated tract has become less in amount and has approached quite close to the circumfereirce, leaving only a narrow band of healthy fibres in the position of the direct cerebellar tract, and does not extend as far forward, although the apex of the triangle still touches the surface. There are a greater number ot healthy fibres to be seen between the grey matter and the degeneration ' than in the cervical or upper dorsal regions. In the lumhar regioii the degeneration is very much less marked than higher in the cord, and occupies the angle formed by the posterior root exit and the circumference. In cases where the lesion in the brain had been extensive the degeneration could be traced as far as the fifth lumbar nerve. I have not carried sections below this point. Summary of Degenerations following Lesions of the Gyrus Fornicatus. The brains and spinal cords of six Monkeys, in which a part or the whole of the gyrus fornicatus had been removed, were examined. In most cases the post-mortem examination showed that the marginal gyrus had also been injured to a variable extent, owing, no doubt, to the difficulty experienced in exjiosing and excising a convolution so deeply situated as the gyrus fornicatus without interfering with the adjacent marginal gyrus. In two instances the removal of the grey matter of the gyrus fornicatus was nearly