The anatomy of the nervous system, from the standpoint of development and function . li themselves a group of dorsal externalarcuate fibers make their way to the restiform body along the dorsal surface ofthe medulla (Fig. 101). According to Cajal these fibers are well developed inman, but absent in the cat and rabbit. The ventral external arcuate fibers aresaid to include a certain number which arise in the lateral reticular and arcuatenuclei and run dorsolaterally over the surface of the medulla to reach thecerebellum by way of the restifrom body (Fig. 104). The arcuate nuclei aresmall irregu
The anatomy of the nervous system, from the standpoint of development and function . li themselves a group of dorsal externalarcuate fibers make their way to the restiform body along the dorsal surface ofthe medulla (Fig. 101). According to Cajal these fibers are well developed inman, but absent in the cat and rabbit. The ventral external arcuate fibers aresaid to include a certain number which arise in the lateral reticular and arcuatenuclei and run dorsolaterally over the surface of the medulla to reach thecerebellum by way of the restifrom body (Fig. 104). The arcuate nuclei aresmall irregular patches of gray matter situated on the ventromedial aspect ofthe pyramid and continuous rostrally with the nuclei pontis, with which they Spinal vestibular nucleus Dorsal external arcuate fibers Tractus solitaries and nucleus Nucleus ofhypoglossal nerve Internal arcuatefibers Dorsal spinocere-bellar tract. Medial longitudinalfasciculus Ventral spinocere-bellar tract Tectospinal trad Medial lemniscus Inferior olivarynucleus Hilus of olivarynucleus Pyramid, cortico-spinal tract. Arcuate nucleus Dorsal motornucleus of vagus Nucleus cuncatusRestiform body Central canal Spinal trad andnucleus N. V Nucleus ambiguus Reticular substance Lateral reticularnucleus Medial accessoryolivary nucleus Inferior olivarynucleus Hypoglossal nerve Ventral externalarcuate fibers Fig. 101.—Section through the medulla oblongata of a child at the level of the olive. Pal-Weigert method. (X 6.) seem to be homologous (Figs. 101, 103). They probably receive fibers from thecerebral cortex by way of the pyramidal tracts; and, if so, the external arcuatefibers which arise from them are homologous with the transverse fibers of thepons. Although the facts stated above are pretty well established, only a small part of theventral external arcuate fibers are thus accounted for. The origin and course of the majorityof these fibers is still obscure. According to Cajal (1909) they arise from the nuclei of thepos
Size: 1555px × 1606px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectnervoussystem, bookye
