A manual of diseases of the nervous system . indicated by the clear area in l. 4, Fig. 70, and faintly in L 75. It is distinguished by a difference in time of development(Flechsig), and by freedom from the secondary degeneration thatinvolves the rest of the column. It is very doubtful whether all the fibres that enter the postero-medisin columns continue in these to the medulla. Some certainly do,but the upward increase in size of the columns seems to be far toosmall for the accommodation of all the fibres that seem to pass to tbe same time we have, at present, no indication of
A manual of diseases of the nervous system . indicated by the clear area in l. 4, Fig. 70, and faintly in L 75. It is distinguished by a difference in time of development(Flechsig), and by freedom from the secondary degeneration thatinvolves the rest of the column. It is very doubtful whether all the fibres that enter the postero-medisin columns continue in these to the medulla. Some certainly do,but the upward increase in size of the columns seems to be far toosmall for the accommodation of all the fibres that seem to pass to tbe same time we have, at present, no indication of the mode inwhich fibres leave these columns. At the medulla oblongata this column becomes filled with nerve-cells, the post-pyramidal nucleus, so called because the highest por-tion of this column has been termed the posterior pyramid of themedulla. It is also called the nucleus g^-acilis. The discovery thatthe fibres of this column are continuous with the nerve-roots investsthe post-pyramidal nucleus with considerable importance, since its. Pig. 78.—Posterior coruu and cplunin at the last dorsal segment. P. M. C, postero-median column ; P. E. C, postero-external column ; P. M. S., pusterior median sep-tum ; p. C, posterior commissure ; v, commissure vein. p. v. C, posterior vesicularcolumn ; C. C caput cornu; p. E., posterior root; a, an artery ; d, d, d, a<ljacentto a strip of the lateral column, indicate the tr;icts ot fibres passing <rom thevicinity and interior of the posterior vesicnlnr column along the septa of thelateral column, to form the direct cerebellar tract; x, x, tracts of fibres passingfrom the neck ot the horn, near the post, vesic. col., to the post-median coluuiii. STRUCTUEE. 181 nerve cells are tlie first with which tbese root-fibres are connected,and they arrest secondary degeneration. The upward degenerationof the median fibres implies upward conduction; their probablefunction will be considered in the next section. The postero-external column ( c
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnervoussystem, bookye
