

305 



by the slight groove above mentioned, into the posterior lateral 

 and posterior median columns. 



The columns of the spinal cord are divided into three chief 

 columns or f uniculi : the ventral, dorsal, and lateral. 



The ventral is subdivided into the following tracts : Descend- 

 ing direct pyramidal tract, sulcomarginal tract, ventral ves- 

 tibulospinal tract (Lowenthal's; anterior cerebellospinal tract); 

 associating association axones between spinal centres and 

 several cranial nerve nuclei, fasciculus ventralis proprius. 



Location of the tracts as regards their distribution within 

 the cord: the direct pyramidal tract extends through the 

 cervical and lower portion of the thoracic, and rarely as low 

 as the lumbar region of the cord; the sulcomarginal tract is 

 found chiefly in the cervical portion of the cord; the ventral 

 vestibulospinal fibers terminate about the ventral horn cells, 

 and have been traced as low as the sacral region. 



The dorsal column is subdivided into the following tracts : 

 Ascending fasciculus gracilis, or tract of Goll, the fasciculus 

 cuneatus, or tract of Burdach; descending the comma tract 

 of Schultze, the median oval tract of Flechsig; associating 

 the fasciculus dorsalis proprius, dorsal cornucommissural 

 tract, septomarginal tract of Bruce, the fasciculus marginalis 

 of Spitzka and Lissauer, the latter is usually described as 

 belonging to the lateral column, but functionally it is more 

 intimately related to the sensor neurone system of the dorsal 

 column. 



The lateral column is subdivided into the following tracts: 

 Ascending dorsolateral spinocerebellar tract of Flechsig, 

 superficial ventrolateral spinocerebellar tract of Gowers, 

 spinothalamic tract, spinomesencephalic tract; descending- 

 crossed pyramidal tract, rubrospinal tract, cerebrospinal 

 tract (Marchi and Lo wen thai), lateral vestibulospinal tract, 

 olivospinal tract of Helwig; associating fasciculus lateral is 

 proprius. 



The posterior cornu is constricted at its base (cervix cornu}, 

 and then expands (caput cornu} before narrowing to its extremity 

 (apex cornu}. Around the latter the neuroglia forms the sub- 

 stantia gelatinosa. , 



The gray matter of the cord consists of nerve fibers, nerve 

 cells, and connective tissue (neuroglia). The nerve cells are 

 for the most part arranged in columns. Of these columns, 

 20 



