ARRANGEMENT OF NERVE CELLS IN SPINAL CORD 583 



Medullated fibers mingled with the small gray fibers about the borders of the 

 gray substance. Mingled with it and supporting it is the meshwork of the 

 neuroglia. 



The multipolar cells of the cord are either scattered singly or arranged in 

 groups or columns in bilateral symmetry. The following are to be distin- 

 guished, certain of the groups being more or less marked in all of the regions 

 of the cord, viz., a, those in the anterior columns; b, those in the lateral 

 columns; c, those in the posterior columns; and d, intrinsic cells distributed 

 throughout the gray matter. 



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.) 



The cells in the anterior columns are large and branching, and each gives 

 rise to an axis-cylinder process which passes out in the anterior nerve root. 

 These cells are everywhere conspicuous, but are particularly numerous 

 in the cervical and lumbar enlargements. In these districts they may be 

 divided into several groups; i. A group of large cells close to the tip of the 

 inner part of the anterior column, i, figure 362. This group is called the 

 antero-mesial group of motor cells. It forms r, column the full length of the 

 cord and is supposed to furnish motor innervation to the long muscles of the 

 trunk. 2. The antero-lateral group of cells, 2a, forms a column which has 

 its best development in the cervical and lumbo-sacral enlargements. It 

 probably furnishes motor fibers to the muscles of the limbs including those 

 of the shoulders and hips. 3. There are groups, 2b, 2C, the intermedio and 

 lateral groups, which form slender columns in the cord, through the entire 



