. A manual of diseases of the nervous system. by thepressure, and interference with function occurs, partly from thepressure and partly from the resulting myelitis. The symptoms pro-duced have, in different cases, many characters in common, althoughthey vary according to the mechanism of the compression and theacuteness of the inflammation. It is only when there aie indicationsthat an acute myelitis has damaged the nerve-elements that we arejustified in regarding the interference with function as an effect ofthe inflammation. Causes.—The morbid processes that may compress the cord arethose tha
. A manual of diseases of the nervous system. by thepressure, and interference with function occurs, partly from thepressure and partly from the resulting myelitis. The symptoms pro-duced have, in different cases, many characters in common, althoughthey vary according to the mechanism of the compression and theacuteness of the inflammation. It is only when there aie indicationsthat an acute myelitis has damaged the nerve-elements that we arejustified in regarding the interference with function as an effect ofthe inflammation. Causes.—The morbid processes that may compress the cord arethose that involve an encroachment on, or occupy part of, the vertebralcanal. The chief are the following:—Disease of the bones of theS]3inal column, especially caries; growths in the spine; aneurismeroding the bones and then compressing the cord ; growths in themembranes; thickening of the dura mater. These processes haveusually only a small vertical extent, and the pressure they exert rarelyextends over more than a few inches, 846 SPINAL Pathological Anatomy, — The cordusually presents evidence of the compres-sion it has endured in considerable nar-rowing at the spot, where it may be in-dented and flattened, or cylindrical. Some-times the reduction in size is extreme; foran inch or so the cord may be reduced toone third of its normal diameter, and ithas even been found no thicker than acrow-quill. An example of flattening isshown in Fig. 106. On the other hand,there is sometimes very little narrowingto be discerned. At the compressed partthe cord is usually grey in tint; its consist-ence is lessened in early cases, and in-creased in those of long duration. Thechange in colour and consistence is dueto the inflammation of the substance of thecord which always results from pressure,and may often be traced for some distanceabove and below the compressed there is much compression there isalways much inflammation, but considerablemyelitis may occur when the amount of
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnervoussystem, bookye
