FIBER TRACTS OF THE SPINAL CORD 



III 



and descend into the spinal cord, within which some of them can be traced to 

 the sacral region. Their collateral and terminal branches end within the an- 

 terior column in relation to the primary motor neurons. 



Other Descending Tracts. The bulbospinal tract (olivospinal tract, tract of 

 Helweg) is a small bundle of fibers found in the cervical region near the surface 

 of the lateral funiculus opposite the anterior column. The fibers arise from 

 cells in the medulla oblongata, possibly in the inferior olivary nucleus, and end 

 somewhere in the gray matter of the spinal cord. The exact origin and ter- 



Fasciculus cuneatus 

 \ 



Fasciculus gracilis 



Lateral corticospinal tract 



Fasciculi proprii 



Ventral corticospinal tract 



- Dorsal spinocerebellar tract 



Oval area of Flechsig 



D. Ill 



L. IV 



Fig. 80. 



Figs. 79 and 80. Diagrams of the sixth cervical, third thoracic, and fourth lumbar segments 

 of the spinal cord, showing the location of the different tracts as outlined by Flechsig on the basis 

 of differences in time of myelination. (van Gehuchten.) 



mination of the tract is unknown. The tectospinal tract, located in the ventral 

 funiculus, is composed of fibers which take origin in the roof (tectum) of the 

 mesencephalon, cross the median plane and descend into the anterior funiculus 

 of the spinal cord, and end in the gray matter of the anterior column. The tract 

 is concerned chiefly with optic reflexes. The vestibulospinal tract, also located 

 in the anterior funiculus, arises from the lateral nucleus of the vestibular nerve 



