26 



Anatomy of the Nervous System 



neurons of the cord or up to the brain, but the exact course 

 of the fibres concerned in this has not yet been demonstrated. 



Eferent Systems. 



The efferent nerve fibres arise from cells situated in the 

 ventral column of the gray matter. These cells are arranged 

 in groups which correspond more or less to the areas of dis- 

 tribution of the fibres and which accordingly differ somewhat 

 in different regions of the spinal cord. The visceral efferent 

 cells form a group of small neurons situated laterally near the 

 base of the ventral column in the thoracic region, this group 

 being called the inter medio -lateral cell column. They lie 

 in a projection of the gray matter into the white matter, 

 which is named the lateral column and which is seen in the 



Fasc. gracilis- 



Fasc. cuneatufi 



Pass, septo-marg. 



Fasc. inter-fascic. 



Tr.cortico^in. lat. 



Tr. nibro-epin. 



Nuc. doreo-lat. 



Nuc. ventro-med. 



Nuc. ventro-lat. 



Tr. cortico-spm. ven . 



Tr. olivo-spinalis 



Tr. tecto-epinalis 



Tr. vestibulo-spin. 



Radix ventralis 



Radix dorsalia 

 Fasc. dorso-lat. 

 Tr. spino-cereb. dor. 

 Columna don'alia 

 Fasc. proprius dora. 

 Fasc. proprius lat. 

 Tr. sp'mo-cereb. ven. 

 Tr. spino-thalam. lat. 

 Columna veotralis 

 Tr. spino-tectalis 

 — Tr. spino-thalam. ven. 

 Tr. spino-olivaris 

 Fasc. proprius ven. 

 Fasc. sulco-marg. 



Fig. 1 



Diagram of transverse section of fifth cervical segment of human 

 spinal cord, from Herrick, Introduction to Neurology. 



On the right side, the area occupied by the dorsal gray column 

 (posterior horn) is stippled; on the left side, some of the groups of cells 

 of the ventral gray column are indicated. In the white matter, the out- 

 lines of some of the more important tracts are schematically indicated, 

 ascending fibres on the right side and descending fibres on the left. The 

 same area of white matter is, in some cases, shaded on both sides of the 

 figure. This indicates that ascending and descending fibres are mingled 

 in these regions. 



