172 



HUMAN PHYSIOLOGY. 



relation by their terminal branches with the nerve-cells in the ventral cornu 

 of the gray matter of the opposite side of the cord. (Fig. 23.) 



A R 



FIG. 23. COURSE OF THE FIBERS FOR VOLUNTARY MOVEMENT. 

 ab, path for the motor nerves of the trunk; c, fibers of the facial nerve; B, corpus 

 callosum; Nc, nucleus caudatus; G, i, internal capsule; N. I, lenticular nucleus; P, 

 pons; N,f, origin of the facial; Py, pyramids and their discussion; Ol, olive, Gr, 

 restiform body; PR, posterior root; AR, anterior root; x, crossed, and z, direct 

 pyramidal tracts. (Landois.) 



Through this decussation each half of the cerebrum governs the muscle 

 movements of the opposite side of the body. 



The fibers composing the crossed and the direct pyramidal tracts are 



