FIBER TRACTS OF THE CORD. 



121 



the lateral and ventral funiculi, rarely the dorsal. Sometimes they cross to 

 the opposite side of the cord through the gray commissure before entering 

 the white substance (Fig. 147). In the white they fork, sending processes 

 upland down; the cord. These give off collaterals which re-enter the cord 

 and branch about the motor cells, the main fiber terminating like its col- 

 laterals. These cells put the different levels of the cord in communication. 

 The r neuraxons from the dorsal nucleus (Fig. 147) differ from these in that 



d-U. 



v.l.s. 



v.ro.f. 



FIG. 147. DIAGRAM OF THE SPINAL CORD. 



The principal fiber bundles are outlined on the left; the predominant courses of the nerves within them 



are indicated on the right. 

 Dorsal funiculus: 



f. g., fasciculus Rracilis [column of Goll]. 



f. c., fasciculus cuneatus [column of Burdach]. 

 Lateral funiculus: 



f. c. 1., fasciculus cerebrospinalis lateralis [crossed pyramidal tract]. 



f. c., fasciculus cerebellospinalis. 



f. v. s., fasciculus ventrolateralis superficialis [Gowers 1 tract]. 



f. 1. p., fasciculus lateralis proprius [ground bundle]. 

 Ventral funiculus' 



f. v. p., fasciculus ventralis proprius. 



f. c. v., fasciculus cerebrospinalis ventralis [direct pyramidal tract]. 

 Columns, d. c., dorsal; 1. c., lateral; v. c., ventral. 



d. n., dorsal nucleus. 

 Sulci, d. m. s., dorsomedian; d. 1. s., dorsolateral ; v. 1. s., ventrolateral; v. m. f., ventromedian fissure. 



their neuraxons go to the cerebellum in a bundle called the fasciculus 

 cerebellospinalis. The spindle shaped cells of the zona spongiosa are also 

 of the second type. 



The third type is characterized by having all of its processes, the 

 dendrites and neuraxon, remain within the gray substance. The neuraxons 

 are much branched, and may cross to the opposite side of the cord. 



There are therefore three types of nerve cells in the gray substance, 

 namely, (i) the cells with processes which enter the peripheral nerves; 



