654 



STRUCTURE OF THE SPINAL CORD 



[CH. XLV. 



Goll 



and from these cells fresh axis-cylinders carry up the impulse to the 

 cerebellum in what are called the cerebellar tracts, while the main 

 fibre (8) may terminate in any of these ways at a higher level 

 in the cord, or above the cord in the medulla oblongata. A certain 

 number of posterior root -fibres, however, cross the middle line and 

 pursue their way up to the bulb in the ascending tracts of the 

 opposite side of the cord. 



In general terms the anterior root-fibres pass out of the grey 

 matter of the anterior horns, and after a short course leave the spinal 

 cord in the anterior spinal nerve-roots. The posterior roots, on the 

 other hand, do not pass to any great extent into the grey matter 



immediately, but into the white 

 matter on the inner side of the 

 posterior horn ; in other words, 

 they go into the column of 

 Burdach (fig. 402); they pass 

 up in this column, but gradu- 

 ally approach the 'middle line, 

 and are continued upwards to 

 the medulla in the column of 

 Goll; but as they go up they 

 become less numerous, as some 

 terminate in the grey matter of 

 the cord on the way in the 

 manner described. A few fibres 

 of the posterior root, however, 

 travel for a short distance in a 

 small tract on the outer side of the posterior horn ; this is called the 

 tract of Lissauer (fig. 404); the comma tract (fig. 403) has been 

 already explained. 



Suppose now one cuts through several posterior roots between the 

 spinal ganglia and the cord, so that the course of degeneration may 

 be more readily traced. Immediately below the points of entrance of 

 these nerve-roots, the comma tract will be found degenerated ; imme- 

 diately above, the degenerated fibres will be found in the column of 

 Burdach ; higher up in the cord they will be less numerous, and have 

 approached the middle line ; the fibres which enter the cord lowest 

 get ultimately nearest the middle line, so that the greater part of the 

 column of Goll is made up of sensory fibres from the legs ; the fibres 

 which enter the cord last, for instance those from the upper limbs 

 and neck, pursue their upward course in the column of Burdach. 



The preceding figure (fig. 402) shows the degeneration in a section 

 of the spinal cord, after the division of a number of nerve-roots on 

 one side. The microscopic section is taken high up, so that all the 

 degenerated fibres have passed into the column of Goll on the same 



FIG. 402. Degeneration in column of Goll after 

 section of posterior nerve-roots. 



