THE TRACT OF LISSAUER AND THE SUBSTANTIA 

 GELATINOSA ROLANDI 



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The Anatomical Lahonilorij of the Xoiihtce.^tcrn Unii'trxih/ Medical School 



ELEVEN FIGURES 



There is located in the apex of the cokunua posterior between 

 the substantia gelatinosa Rolandi and the periphery of the spinal 

 cord an area of rather widely separated small niedullated fil)ers. 

 These fibers, having for the most part a vertical course, form a 

 tract which is easily distinguished in Pal-Weigert preparations, 

 in which it takes a lighter stain than the remainder of the sub- 

 stantia alba. It has for this reason usually l:>een considered a 

 part of the columna posterior, although it is admitted by all 

 that it properly belongs with the longitudinal fiber tracts of the 

 cord. 



In 1885 Lissauer observed that fine medullated fibers grouped 

 themselves on the lateral side of an entering rootlet, and, turn- 

 ing lateral ward, separated themselves from the remainder of the 

 radicle to enter the apex of the columna posterior. Here the}^ 

 turned to run vertically in the tract which now bears his name. 

 These observations were confirmed by Bechterew, 1886. The 

 general acceptance of these observations was facilitated l)y the 

 results obtained shortly afterward by the application of the (iolgi 

 stain to the spinal cord. A number of observers, among them 

 Kolliker ('91) working with foetal or newborn mammalian tissue, 

 were able to show that the fillers of the entering dorsal root sep- 

 arate into two bundles, a lateral bundle of ver}- fine axons and 

 a medial bundle of much coarser ones. The lateral bundle of 

 fine axons runs into Lissauer's tract, where the fibers divide into 

 ascending and descending branches. The ascending limbs run 

 upward in the tract for some distance, but the descending linil)s 

 are very short (Barker '99). This clear evidence in regard to 



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THE AMERICAN JOURNAL OF ANATOMV, VOL. IC), NO. 1 



