Anatomical and physiological observations. Pt. I / by John Struthers.

  • Struthers, John, 1823-1899.
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Anatomical and physiological observations. Pt. I / by John Struthers. 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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    instance the fibres towards the cerebellar peduncles could be ti-aced, he states, into the interior of the cerebellum. Farther, Valentin, with characteristic minuteness, describes (p. 278) an arrangement of the fasciculi, as if this nerve consist- ed of two distinct roots or parts where it issues from the cms,— an internal portion ( pai's interna), fonned by anterior as well as posterior fasciculi, and an external portion ( pars externa), from the inferior and internal parts of the crus, which converges on the outside of the other. The latter description appears t o be correct enough, but still without authorising the inference that there are two roots physiologically distinct. The external portion arises only a very little higher up, as the brain lies for dissection, and, as it were, natiu^ally so, from the manner in which the nerve comes out, and then abruptly winds round the inside of the crus. On carefully separating the fasciculi of each por- tion, I found, in one brain, the outer portion to consist of eight or nine fasciculi, and the internal portion of nineteen. In an- other, the outer portion contained fifteen fasciculi, and the inner portion eighteen or nineteen. The smaller part lies at first be- tween the greater portion and the crus, but the fasciculi of the two portions very soon unite and interlace. In fact there is no arrangement such as would have suggested to rhe that there were to this nerve two distinct roots, worthy of being so named and described ; and I have noticed it only as Valentin has connected it with his view, founded on the result of his experiments on rabbits, that tlie third nerve is sensory as well as motor, from its origin. Of the deeper connections of the third nerve, Swan^ observes, that its origin may be traced in the direction towards that of the superior oblique oculo-muscular nerve. Mr Solly^ again states, that it will be found not merely to be connected with the surftice of the crus cerebri, but dipping beneath it, and there dividing into two portions;—one of these ascends through the pons Varolii to be connected with the motor tract in its passage through that commissure; the other passes through the locus I A Demonstration of the Nerves of the Human Body. 1830 P 19 ' Op. cit., p. 293. ■ ■ 0