ARRANGEMENT OF NERVE CELLS IN THE SPINAL CORD 545 



the coordinations of muscular movements. The nerve relations and the 

 restricted location of the posterior vesicular column has also led to the sugges- 

 tion that its function has to do with the visceral afferent or sensory nerve 

 impulses. Sensory fibers from the posterior roots arborize around the cells 

 of the posterior vesicular column, i.e., the dorsal nucleus, see figure 363. 

 The dorsal nucleus is considerably broken up by the passage of bundles of 

 fibers through it, called the lateral reticular formation. 



Besides these groups, which have their names largely on account of their 

 ocation, there are distributed throughout the gray matter a very large num- 

 ber of other cells, which are known as intrinsic cells. These are of two types, 



FIG. 362. Section of Spinal Cord, One Half of Which (Left) Shows the Tracts of the 

 White Matter, and the Other Half (Right) Shows the Position of the Nerve Cells in the 

 Gray Matter. 7, 10, 9, and 3 are tracts of descending degeneration; i, 2, 4, 6, and 8, of 

 ascending degeneration. Semidiagrammatic. See the text for a description of the groups 

 of nerve cells shown on the right. (After Sherrington.) 



those restricted to connections wholly within the gray matter, and those that 

 send out axones which pass into the adjacent ground bundles of the same 

 or of the opposite side, and pass up and down the cord, to enter the gray 

 matter again. They connect by their end-brushes with cells at different 

 levels of the cord. 



The functions of these connecting or intrinsic cells is to unite the pos- 

 terior and anterior regions of the cord, to serve as conductors between the 

 lateral halves, or to connect segments at different levels. They are also dis- 

 tributing fibers in that they bring a single or at least a small number of pos- 

 terior sensory neurones into connection with a relatively large number of 

 anterior or motor neurones. 

 35 



