Human anatomy, including structure and development and practical considerations . phe and immediately beneath the gray matter flooring the Syhianaqueduct and the fourth \entricle (Figs. 959, 961). In the lower ])art of the medulla,the bundle gradually leaxes the ventricular floor and rests upon the dorsal border ofthe median fillet, and, at the level of the pyramidal decussation, where the fillet nolonger intervenes, lies behind the pyramid and at some distance from the , it assumes a more ventral position, to the medial side of the isolated anteriorcornu, and, finally, enters th
Human anatomy, including structure and development and practical considerations . phe and immediately beneath the gray matter flooring the Syhianaqueduct and the fourth \entricle (Figs. 959, 961). In the lower ])art of the medulla,the bundle gradually leaxes the ventricular floor and rests upon the dorsal border ofthe median fillet, and, at the level of the pyramidal decussation, where the fillet nolonger intervenes, lies behind the pyramid and at some distance from the , it assumes a more ventral position, to the medial side of the isolated anteriorcornu, and, finally, enters the anterior column of the cord to be lost within the upperpart of the ground bundle. The fasciculus includes association fibres of varying lengths, some of which areascending and others descending paths. The constitution of the bundle is, there-fore, continually changing, the loss of certain fibres being replaced by the additionof others. Its fibres are among the very first in the brain to become medullated, andbegin to acquire this coat during the fourth foetal month ( Hbsel).. Diagram showing chief afferent constituents of median fillei. Till-: MI-:SENCEIII.\I.()N. Notwitlistandinj:: tlu- ;uliuittc-cl im|)ortance of the tract and tlie prolonged study that it hasreceived, iiuicli n-iiiains to he tiettrmiued coiUL-rninj; tiie source and coniu-ctions of tiie manyconstituents uiiicii und(nit)tediy go to form llu- huntlle. Amonj; tiie more certain of these com-ponents tlie foilouins may be mentioned : 1. At tlie upper v\h\ of ilie fascicuhis a considerable number of fibres arise from the cellsof the nucleus of the posterior commissure, t)r DarkschcwHschs hih/cks, which lies in advanceof the oculomotor nucleus, within the };ray matter ; the superior end of the Sylvianacjueduct. Accordiiiij to Iulini;c-r an additional contingent takes origin from a nucleus (n. fas-ciculi lonj;itii( dorsalis) within the gray matter of the floor of the third ventricle in the \ icin
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Keywords: ., bookauthormc, bookcentury1900, bookdecade1910, booksubjectanatomy
