142 THE SURGICAL PHYSIOLOGY 



sensations are conducted in this way and in this way 

 only ; tactile sense can take either this path or the 

 more direct route by the posterior columns. 

 A tumour of the spinal cord : 



1. May affect the nerve-roots, in which case the 

 symptoms may be confined to those roots. 



2. May press on one side of the spinal cord. In 

 this case there is usually pain radiating along the 

 nerve-roots involved at the same time, which is 

 important in the diagnosis. 



Let us take the case of a tumour in the left lower 

 cervical area. This will involve : 



(i). The emerging roots of the lower cervical nerves 

 on the left side, causing pain, dulling of sensation, 

 and flaccid paralysis with loss of reflexes, wasting, 

 and reaction of degeneration, in the left arm. 



(ii). The pyramidal, rubrospinal and vestibulo- 

 spinal tracts on the left side, causing paralysis of 

 the left leg. Inasmuch as the pyramidal and rubro- 

 spinal tracts are involved, muscular tone will be 

 greatly increased ; the impulses leading to this 

 increase perhaps descend on the other side of the 

 cord. There will be, therefore, rigidity of the left 

 leg and exaggerated reflexes. 



(iii). The cerebellar tracts and posterior columns of 

 the left side, causing loss of muscle and joint sense, 

 and loss of tactile discrimination and recognition of 

 objects on the left side. 



(iv). The chain of nerve-cells and axons by which 

 heat, cold, and pain travel up from the right leg, will 

 also be pressed upon. 



Tactile sense may or may not be lost in either 



