Section III. 



DISEASES OF THE PERIPHERAL NERVOUS 

 SYSTEM. 



General Etiology and Symptomatology of the Diseases of the 

 Peripheral Nerves. 



A variety of causes are responsible for diseased condi- 

 tions of the peripheral nerves. 



Traumatic injuries are frequent causes of such conditions. 

 In the first place a superficial nerve may be crushed between 

 the underlying bone and some hard object, or more rarely be- 

 tween a muscle in a condition of powerful contraction and the 

 bone. In a number of cases nerves are injured by blows, or 

 penetrating wounds, but tearing of a nerve owing to sudden 

 excessive extension of a limb is observed only very occasionally. 

 Solution of continuity of the nerves is rarely met with in cases 

 of wounds of the surrounding soft tissues or fractures of bones. 



Compression of nerves may result from the development of 

 neoplasms either around the nerve, in its immediate neighbor- 

 hood, or even in the nerve itself. Neuromata occur almost ex- 

 clusively, but with moderate frequency in the ox. It is only 

 exceptionally, however, that they give rise to any svmptoms 

 (Zietschmann, S. B. 1900, 234; Detroye, Rev. Vet. 1907, 408). 

 As a rule, several nerve trunks of the head, trunk and limbs 

 are involved simultaneously, and they also occur on connec- 

 tion with the fibers and ganglia of the sympathetic. They are 

 composed of fibrous and gelatinous tissue and arise in connec- 

 tion with the interstitial tissue of the nerves, the nerve ele- 

 ments remaining uninjured. In some cases, amputational neu- 

 romata develop after neurotomy has lieen performed, and they 

 are the cause of severe pain. 



Nerves may suffer compression owing to the existence in 

 their neighborhood of enlarged and indurated hmiphatic glands, 

 effusions of blood, abscesses, foreign bodies, parasites (larva? 

 of TTypoderma), dislocations of bones and calluses resulting 

 from fractures of bones. 



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