. The elements of pathological histology with special reference to practical methods . um with thecolumns of Clarke in the spinal cord. The remaining bundles in theanterior columns are called the basis bundles of the anterior columns, 336 THE CENTRAL NERVOUS SYSTEM and those in the lateral columns the mixed zones. Lastly, themedian portion of each posterior column is named the column ofGoll or fitniculis gracilis, and the lateral portion the coktmn ofBiirdacli or funiculus cuneatus. Secondary degeneration may be ascending or descending. Thelatter (Fig. 162) most frequently affects the pyramida
. The elements of pathological histology with special reference to practical methods . um with thecolumns of Clarke in the spinal cord. The remaining bundles in theanterior columns are called the basis bundles of the anterior columns, 336 THE CENTRAL NERVOUS SYSTEM and those in the lateral columns the mixed zones. Lastly, themedian portion of each posterior column is named the column ofGoll or fitniculis gracilis, and the lateral portion the coktmn ofBiirdacli or funiculus cuneatus. Secondary degeneration may be ascending or descending. Thelatter (Fig. 162) most frequently affects the pyramidal tracts, occur-ring in cases where the motor centres in the cerebral cortex, or thesystem of motor fibres passing downwards from them through thecorona radiata, internal capsule, crusta of • the crura cerebri, andpyramidal tracts, are destroyed at any spot. Th,e ascending degenera-tion occiffs after destruction of the cord or posterior spinal nerveroots. Immediately above the site of the lesion it affects the wholeof the posterior columns, but further up the column of Goll Fig. 162.—Secondary Descending Degeneration of the Right Crossed PyramidalTract in the Cervical Region of the Cord, in cerebral softening due to embolism ofthe Left Arteria fossae Sylvii. About x 5. (Ammonia carmine.) a, Grey degenera-tion of the crossed jiyramidal tract; h, Anterior horns; c, Posterior horns ; d, Whitesubstance. When the lesion has occurred in the upper dorsal region, the directcerebellar tracts also degenerate above it. The more minute pro-cesses in secondary degeneration, which make themselves perceptibleas early as the second week, are not unlike those in softening, asthey also consist in disintegration of the nerve-fibres and formationof granule corpuscles, whilst the empty spaces thus left are filledup partly with fiuid and partly with growing neuroglia. At theearliest period the degenerated tracts still contain many of the pro-ducts of disintegration, and hence to the naked
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpatholo, bookyear1895
