256 DISEASES OF THE SPINAL CORD 



INFLAMMATION OF THE COVERINGS OF THE CORD. 



Acute Spinal Meningitis. Meningomyelitis. 



From a pathological standpoint may be distinguished : (a) 

 Spinal meningitis, an inflammation of the meningeal cover- 

 ings of the cord. If the hard spinal membrane is involved, a 

 spinal pachymeningitis is spoken of; if the soft, a spinal 

 leptomeningitis, (b) Myelitis, an inflammation of the sub- 

 stance of the cord. In practice the inflammation so com- 

 monly involves both the cord and its coverings that the term 

 meningomyelitis is usually most applicable to the condition. 



Occurrence. — Spinal meningitis is a rather rare disease in 

 horses except when it occasionally assumes an enzootic dis- 

 tribution. 



Etiology. — The principal cause of spinal meningitis is 

 infection. The condition is rarely secondary to acute infec- 

 tious diseases, such as infectious pneumonia of the horse, 

 strangles, pyemia and septicemia. It may also result from 

 inflammation which exists in the neighborhood of the cord, 

 such as caries of the vertebrae, abscesses which erupt into the 

 vertebral canal and it is possible that infection may be carried 

 along the nerve trunks to the cord and its coverings. A 

 primary spinal meningitis may be occasionally the result of 

 traumatism, such as a blow over the back, or rarely where a 

 horse's tail is docked too closely. In very rare instances 

 sharp pointed foreign bodies which have been swallowed 

 by cattle have wandered into and injured the cord. The 

 form of inflammation may be either serofibrinous or suppura- 

 tive. 



Symptoms. — ^The gait of the animal affected is usually stiff, 

 straddling and labored. In the first stages the skin over 

 certain areas, especially in the region of the back, is extremely 

 sensitive. Stroking the animal in a direction contrary to the 

 lay of the hair causes severe pain, the patient arching the 

 back, becoming restless and making every effort to evade the 

 examiner. Striking the tops of the spines of the vertebrae 

 with the handle of a percussion hammer may cause the 

 animal to evince pain. 



Groups of muscles show twitching or more marked spasm- 



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