THE SPINE. 379 



sible functions. The information evolved from 

 these sources makes a classification of tracts, in the 

 cord, possible. 

 Tracts of the Cord. POSTERIOR REGION. 



1 . Column of Goll. This lies adjacent to the dorsal 

 fissure and extends the whole length of the cord. 

 Its fibers arborize about nerve cells in the nucleus 

 gracilis of the lower region of the medulla. 



2. Column of Burdach. This extends parallel to 

 the column of Goll between the latter and the pos- 

 terior horn of gray matter. It extends the whole 

 length of the cord and its fibers arborize about nerve 

 cells in the nucleus cuneatus of the medulla, adjacent 

 to the nucleus gracilis. The column of Goll becomes 

 wider in the upper portions of the cord and that of 

 Burdach narrower. This is due to nerve fibers that 

 gradually pass into the column of Goll from the col- 

 umn of Burdach on their way to the brain. 



3. Comma Tract. This is a small tract found in 

 the column of Burdach, and represents sensory 

 fibers from the posterior roots of the spinal nerves 

 that pass down the cord for a short distance, and 

 then turn into the anterior horn of gray matter to 

 arborize about nerve cells of this region. 



4. Lissaur's Marginal Ground Bundle. This is a 

 small commissural tract placed near the surface of 

 the cord just lateral to the entrance of the posterior 

 root fibers. It is formed by some of the fibers of 

 this root. The tract extends the whole length of 

 the cord, but each individual fiber runs but a short 

 distance and then turns inward to arborize about 

 nerve cells of the posterior horn. 



