An anatomico-physiological study of the posterior longitudinal bundle in its relation to forced movements / by L.J.J. Muskens.
- Muskens, Louis Jacob Josef, 1872-1937.
- Date:
- 1914
Licence: In copyright
Credit: An anatomico-physiological study of the posterior longitudinal bundle in its relation to forced movements / by L.J.J. Muskens. 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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![at least in the oral parts ol' the vestibular region, and terminating in the region of the posterior commissural nucleus. This bundle may be styled the homolateral vestibulo-mesencephalic fasciculus. This tract is only partially identical with that described anatomically by Probst [124]. Van Gehuchten [63] in 1904 suggested that the whole of the lateral part of the posterior longitudinal bundle (fasciculus Deiters’ ascendens, Lewandowsky,- Winkler [169]) consisted of fibres, ascending from Bechterew’s nucleus. This origin, for this limited portion at least of the posterior longitudinal bundle, may now’ be held as proved [cf. 108], as may also the association of its upward degeneration with circus movements or conjugate deviation to the normal side. Both the circus movements observed after lesion of the homolateral or crossed vestibulo-mesencephalic tracts are associated with conjugate deviation of the head and eyes to the side of the movement, or with loss of lateral deviation of the eyeballs to the opposite side. (6) According to the notions advanced by Duval, Bleuler, Edinger, Bischoff, Spitzer, Kohnstamm, Bernheimer, Fraser, Wallenberg, Wiersma, and others, the posterior longitudinal bundle represents a combination of ascending and descending tracts, which control the co-ordinated movements of the eyes, head, and trunk, and control or direct the maintenance of the equilibrium of motion. Now, from experimental data furnished by the present investigation, it is seen that after a direct lesion in the region of the posterior commissure of the cat on one side, where the resulting circus movements were directed to the side of the lesion, a descending tract degenerates which lies at the innermost part of the posterior longitudinal bundle of the same side. This tract probably originates in the posterior commissural nucleus. As it stops short in the medulla it is suggested that it may be termed the fasciculus commissuro-medullaris [cf. 108]. (7) Although it is probable that this mesencephalo-medullary tract, exists in all the higher organized vertebrates such as selachians, teleosteans, amphibians, reptiles, birds and mammals, it is only in the mammal that a destructive lesion of the nucleus and of its efferent tracts from the striate body is associated with circus movements towrards. the side of the lesion. In the lower animals a lesion oral to the posterior commissure is not followed by any circus movements. The anatomical explanation of this fact seems to be that only in mammals are the hypothalamic and commissural nuclei sufficiently connected with the prosencephalon that section of the connexions should be followed by asymmetrical locomotion, as evidenced in circus](https://iiif.wellcomecollection.org/image/b22447799_0075.jp2/full/800%2C/0/default.jpg)
