THE SPINAL CORD 551 



side, in the posterior portion of the lateral columns and are bounded 

 internally by the posterior cornua of gray matter and externally by 

 a narrow band called the direct cerebellar tract. In following the col- 

 umns upward, it is found that they pass forward in the upper part of 

 the cervical region and decussate in the lower portion of the anterior 

 pyramids of the bulb. These are descending tracts, and their fibres 

 undergo descending secondary degenerations as the result of destruction 

 of certain motor areas in the brain. 



3. Anterior Ground Columns. These fasciculi are bounded inter- 

 nally by the columns of Tiirck and externally by the anterior cornua of 

 gray matter and the anterior roots of the spinal nerves. Their fibres 

 are supposed to connect the gray matter of the anterior cornua of the 

 cord with the gray matter of the bulb. 



4. Lateral Btmdles. These columns lie in the lateral portion of 

 the cord externally to the anterior cornua of gray matter and the gray 

 commissure. Their fibres are supposed to connect the gray matter of 

 the cord with the gray matter of the bulb. 



5. Ascending and Descending Cerebellar Fasciculi. These are situ- 

 ated externally to the lateral bundles. They are supposed to connect 

 the gray matter of the cord with the cerebellum. 



The fibres of the anterior ground columns and the lateral bundles 

 do not degenerate in either direction as the result of section of the 

 cord. Their fibres seem to connect nerve-cells with each other, and 

 their trophic cells exist at both extremities, which accounts for the ab- 

 sence of degeneration just mentioned. 



6. Direct Cerebellar Fasciculi. These fasciculi are situated at the 

 outer and posterior portion of the lateral columns. Their fibres pass to 

 the funiculi graciles, or posterior pyramids of the bulb, and thence to 

 the cerebellum, by the inferior peduncles. They connect the cells of the 

 posterior cornua of gray matter with the cerebellum. These columns 

 make their appearance first in the lumbar region of the cord, and they 

 increase in size from below upward. After section of the spinal cord, 

 the fibres of the direct cerebellar fasciculi show ascending secondary 

 degenerations. Their trophic centres probably are the cells of the pos- 

 terior cornua of gray matter. 



7. Columns of Burdock {Posterior Lateral Columns). These col- 

 umns are in the posterior portion of the cord, between the columns of 

 Goll and the posterior cornua of gray matter. Their fibres connect 

 certain of the cells of the gray matter of the posterior cornua with the 

 cerebellum ; or at least the fibres pass upward and are connected with 

 the restiform bodies, going to the cerebellum through the inferior pe- 

 duncles. The fibres also connect nerve-cells in different planes of the 



