THE CEREBRUM 



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FIG. 84. Scheme of relationship of cells and fibers of brain and cord. 



(Kirkes.) 



Pyr, cell of Rolandic area; Ax, its axis cylinder crossing the middle line AB, 

 to enter one of the pyramidal tracts; the collateral Call goes to the cortex of 

 the opposite hemisphere, while another, str, enters the corpus striatum. The axis 

 cylinder arborizes around an anterior horn cell, whence a motor fiber goes to the 

 muscle. 



The axis cylinder from the spinal ganglion cell is represented as bifurcating 

 and sending one branch to the periphery and one to the cord; the latter itself 

 bifurcates, the lower division ending as shown better in Fig. 77. N.G., cell in 

 posterior cornu of the cord or posterior column of the bulb. The distance of 

 this cell from the point of entrance of the axis cylinder into the cord may be 

 great or small. Note the collaterals from it in Fig. 77. I. A., decussating fiber 

 ending at cell in optic thalamus, O.T., from which a fiber passes to the cortex. 

 A collateral is shown passing from the ascending sensory fiber to a cell of 

 Clarke's column, whence a fiber passes to a cell, P, of the cerebellum. 



