94 NERVOUS SYSTEM. 



The following sections of the human spinal cord are for the purpose 

 of studying the regional differences presented by it, and are all pre- 

 pared in the same way. (p. 23, s. Eosin, m. B.) 



Conus medullaris. (L) The white substance forms a narrow 

 margin around the central grey matter. The horns are 

 rounded and the commissure is broad. The lateral portion of 

 the ventral horn contains a number of large nerve cells. The 

 dorsal root is broad at its entrance into the cord. (H) Find 

 the groups of cells in the ventral horn, and note the group 

 previously mentioned (probably a limb area, Sherrington). The 

 cells of the central canal are usually well seen. 



Lumbar cord. The whole section is larger than the last, 

 and there is much more white substance. The ventral horns 

 are much more bulbous and contain many large nerve cells, 

 (If) chiefly in its ventral and lateral portions. The dorsal 

 horn is also rounded and the dorsal nerve root sends strands 

 of fibres along the mesial side of the horn to enter its sub- 

 stance nearer the neck. The central canal is wider trans- 

 versely. 



Cervical cord. The whole section is larger and somewhat more 

 oval transversely, and there is a proportionately greater amount 

 of white substance in the posterior columns. The grey matter 

 is slimmer-looking than in the lumbar region though its mass 

 is about the same. The ventral cornu is more expanded later- 

 ally, the angular recess between the ventral and lateral horns 

 being, as in the lumbar region, filled up with cells containing 

 grey matter. In the upper cervical region this protuberance 

 diminishes and the lateral cornu becomes prominent through 

 the emergence at that point of the fibres of the spinal accessory 

 nerve. 



Bulb. T.S. Man, below the olive, (p., &c., the same as 

 for the last.) The canal is still central. The ventral cornu 



