I320 



A li^ANUAL OF ANATOMY 



The posterior column is situated between the posterior median 

 fissure and the posterior cornu of grey matter, its superficial limit 

 being the fasciculi of the posterior nerve-roots at the postero-lateral 

 sulcus. 



The white matter increases in quantity from below upwards, 

 and septa of pia mater and neuroglia fibres pass into it at various 

 points. 



Chief Distinguishing Characters of the Spinal Cord in Different Regions^ 

 as seen in Transverse Sections. 



Minute Structure of the Spinal Cord— Grey Matter.— The grey 

 matter consists of nerve-cells, nerve-fibres, and neuroglia, and is 

 very vascular. 



The nerve-cells are present in great numbers, and are multi- 

 polar. Each cell sends off at various points several protoplasmic 

 processes, one of which becomes the axis-cylinder of a nerve-fibre, 

 and is called the axis-cylinder process, or axon. The other processes 

 are known as the protoplasmic processes of Deiters, or de^idrites, 

 and, after successive branchings, they terminate in free extremities. 

 There are no anastomoses between the dendrites of the same cell, 

 nor between those of contiguous cells. A multipolar nerve-cell, 

 with its axon and dendrites, constitutes a neuron. The multipolar 



