138 



CHAPTER X. 



THE SURGICAL PHYSIOLOGY OF THE 

 SPINAL CORD. 



The effects of division of the posterior nerve roots. The diagnosis 

 and localization of tumours of the spinal cord. The exact diagnosis 

 of injuries of the spinal cord. 



THE EFFECTS OF DIVISION OF THE 

 POSTERIOR NERVE ROOTS. 



THE effects may be classified as follows : 

 i. Anaesthesia of the spinal area of skin 

 supplied. The distribution of these in the human 

 subject has been worked out thoroughly, and the 

 charts of Head, Sherrington and others are well 

 known. Section of a single nerve root scarcely ever 

 causes any complete loss of sensation. 



2. Ataxia of the corresponding limb, which may be 

 severe. 



3. Loss of tone, leading to marked flaccidity of 

 the corresponding limb. 



4. A variable degree of functional paralysis. 

 Owing to the loss of sensory impulses, the ataxia, 

 and lack of tone, the patient, man or animal, prefers 

 not to use the limb, although there is not a genuine 

 paralysis. 



5. Loss of reflexes. 



6. Trophic lesions, such as ulcers, whitlows, etc. 



7. Usually not shock. This is rather surprising. 



