236 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 commonly 

 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 in- 

 fection. The condition is rarely secondary to acute infectious 

 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 vertebra, 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 inflamma- 

 tion may be either serofibrinous or suppurative. 



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 vertebra? 

 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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