. A manual of diseases of the nervous system. s tissue is often more abundant, and forms a more distinct SYEINGOMYELIA. 633 mass, lower down the cord,below the cavity. A goodexample of tliis condition inslight degree is presented b\the cord, the seat of chronicmyelitis, represented at , p. 385. In the cervicalregion (a) there is a largecentral canal, bounded by athick layer of gliomatoustissue. In the inner part ofthis tissue, limiting the cavity,is a sinuous membrane, fibrousin structure. The origin ofthis membrane is not easy toexplain, but it is often foundin cavities of this charact
. A manual of diseases of the nervous system. s tissue is often more abundant, and forms a more distinct SYEINGOMYELIA. 633 mass, lower down the cord,below the cavity. A goodexample of tliis condition inslight degree is presented b\the cord, the seat of chronicmyelitis, represented at , p. 385. In the cervicalregion (a) there is a largecentral canal, bounded by athick layer of gliomatoustissue. In the inner part ofthis tissue, limiting the cavity,is a sinuous membrane, fibrousin structure. The origin ofthis membrane is not easy toexplain, but it is often foundin cavities of this character,and is evidence of the similarnature of those that differmuch in other respects. Inthe lumbar region (b) thetissue, which bounds the cavityia the other section, forms alarge round mass in the posi-tion of the canal, obliterating a central cavity ap-pears not to be the canal itself,but to be situated behind, it isthen apparently often due to apersistence of the fore-part oft^s posterior portion of thecanal, after the posterior com-. FlG. 186.— Syringomyelia, from acase of tumours of the pons andCauda equina, with some diffuse ^^ ^ Bcleiosis in the dorsal region of *%v the cord. A, B, and C are sections ^^ of the cervical enlargement. The -il-- Z large cavity iu A is perhaps the •%;^-^- dilated canal, since it is lined in W/ £• front with epithelium, but in front of it, in the posterior commissure, is a group ofnuclei like an obliterated canal. The zone of tissue around the cyst is composed ofinterlacing fihres and nuclei, and processes extend from it into the posteriorcolumns both in front and behind. In B the cavity is smaller and the wallthicker, while in C the tissue about it forms a considerable mass, and a second smallcavity has formed in the middle line, apparently by the brenking down of the the dorsal region (D) there was merely an unusually large accumulation of nucleiin the position of the canal, which, in the lumbar region, bad the normal a
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectnervoussystemdisease
