514 



THE NERVOUS SYSTEM 



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

 terior neurones into connection with a relatively large number of anterior neu- 

 rones. 



Columns and Tracts in the White Matter of the Spinal Cord. In 

 addition to the columns of the white matter which are marked out by the 

 points from which the nerve roots issue, and which are the anterior, the lateral, 

 and posterior, the posterior is further divided by a septum of the pia mater into 



Radix anterior 

 Fasciculus cerebrospinalis lateralis fpyramidalis lateralis] * 



Anterior root fibre 



Bundle to anterior funiculus from the formatio reticularis 

 Fasciculus cerebrospinalis antei 

 [pyramidalis anterior} 



Bundle to anterior funiculus ^ 

 from the formatio reticularis \ 



Substantia grisea. 



Fasciculus 



anterolateraUs super- 



ficialis fGowersi] and <... 



(ascending) bundle from 



anterior funiculus to the 



formatio reticularis 



Substantia alba 



Bundte" to lateral 

 funiculus from Deiters* 

 nucleus and from Hhe 

 red nucleus . 



Fasciculus cerebto 



spinalis lateralis 



(pyramidalis lateral! 



Nervus spinalis 



Ganglion spinale 

 Cells of tho spinal ganglion 

 / Fasciculus cerebellospinalis 

 ,. Secondary reflex path 



, Radix posterior 



Collateral 



- to the posterior horn 



Secondary path of 



- posterior funiculus 

 .Descending posterior 



root fibre 



Primary reflex path 

 -- Ascending posterior 

 root fibre 



Secondary reflex path 



. .Descending posterior 

 root fibre 



- Posterior TOO t fibre 



Sulcus nietjianv 

 posterior 



--- Posterior root fibre 



FIG. 361. Reconstruction of a Segment of the Spinal Cord Representing Both a Transverse 

 and Longitudinal Section. (Held, from Spalteholz's Anatomy.) 



two almost equal parts, constituting the postero- external column, or column of 

 Burdach, figure 360, 2, and the posiero-median, or column of Goll. In addition 

 to these columns, however, it has been shown that the white matter can be still 

 further subdivided. This subdivision has been accomplished by evidence of 

 several kinds that the parts or, as they are called, tracts in the white matter 

 perform different functions in the conduction of impulses. 



The methods of observation are the following: 



The embryological method. It has been found that, if the development 

 of the spinal cord be carefully observed at different stages, certain groups of 



