444 DISEASES OF THE SPINAL CORD 



Etiology. Mechanical. Common causes of meningo- 

 myelitis are traumatic injuries, such as blows in the region 

 of the back or loins, being run over by vehicles, etc. 



Infectious. It is also seen during or following the infec- 

 tious diseases as distemper, rabies, pyemia, etc., and abscesses 

 in the region of the spine, the pus burrowing between the 

 vertebrae and attacking the meninges and cord occasion it. 



Pathology . The membranes covering the cord are some- 

 what thickened and show either diffuse or circumscribed 

 areas of inflammation, and may be adherent to the cord itself. 

 In other cases, depending on the cause, abscesses may be 

 found involving both the membranes and the cord. If the 

 condition is due to traumatic causes, the vertebrae may be 

 broken or splintered with some portion pressing on the 

 cord. The spinal fluid is increased in quantity and may be 

 purulent in character. 



Symptoms. The symptoms of meningomyelitis, unless of 

 traumatic origin, appear gradually and become more severe 

 as the disease progresses. They may vary from slight motor 

 and sensory disturbances to complete paralysis. There is 

 slight twitching of the extremities which is usually the first 

 symptom noted. 



Disturbances of sensation are frequently observed as 

 hyperesthesia, the animal showing pain when handled or 

 even when stroked with the hand. Symptoms of paralysis 

 are seen later, except when due to severe traumatic causes, 

 when the}' may be the first and only symptoms shown. 

 The patient has a staggering gait, sways from side to side 

 when walking and finally drags its hind limbs. When 

 placed on its feet, it will drop sideways on its hind quarters. 



If the lesion in the cord is far forward, the anterior limbs 

 may also be involved. If in the cervical region, however, 

 death usually follows suddenly from respiratory arrest. 



The sphincters of the anus and urinary bladder are 

 usually involved causing the feces and urine to pass involun- 

 tarily, though there is usually constipation. Progressive 

 paralysis indicates tumors pressing on the cord. If only 

 the membranes covering the cord are involved, the spinal 

 reflex is present and may be exaggerated. If a portion of 



