724 INJURIES TO THE VERTEBRAE. 



Local examination gives negative results in large and well- 

 nourished horses. Crepitation, pain, or displacement of the superior 

 spinous process of the affected vertebra can seldom be detected, 

 except in small, thin animals with slight muscular development. 

 Paraplegia arising from spinal fracture is accompanied by anaesthesia 

 and sweating behind the lesion, and occasionally a hiatus may be 

 seen over the seat of fracture. Twitching of the dorsal and lumbar 

 muscles and convulsive attacks have also been noticed. Correct 

 diagnosis is the more important because prognosis is always 

 unfavourable, and slaughter must be recommended as soon as 

 fracture of the body or arch of a vertebra is recognised. 



In horses, the condition is oftenest mistaken for haemoglobinuria. 

 The history generally clears up this point, otherwise the urine must 

 be examined, though it should not be forgotten that in hsemoglo- 

 binuria the urine occasionally appears normal ; the presence of 

 blood, colouring matter, or albumen would, however, point to the 

 latter disease. In hsemoglobinuria the muscles of the loins and 

 quarters are abnormally hard and firm, but in pressure paralysis 

 there is pronounced relaxation. Again, in hemoglobinuria the 

 visible mucous membranes are more or less reddened, a symptom 

 which certainly does not exist in the early stages of spinal fracture. 

 Diagnosis is more difficult if the animal is unable to rise, or is 

 suffering from fever. 



Thrombosis of the posterior aorta or of the iliac arteries produces 

 similar symptoms, but they are intermittent and only shown when 

 the animal is exercised. In doubtful cases, examination per rectum 

 will settle the point. 



Fractures of the vertebrae are more difficult to distinguish from 

 injuries to the cord, produced, for example, by violent concussion. 

 In the latter case the cord may be partially ruptured, or extravasation 

 into the subdural space may be produced, without the vertebras 

 being displaced ; finally, concussion of the medulla may exist without 

 visible lesions or anatomical changes, a condition clinically described 

 as commotio medullas spinalis. This has repeatedly been seen in 

 dogs and cats, which have fallen out of windows, or been run over, 

 or struck with heavy sticks. When injuries of this sort are 

 accompanied by rupture of the cord or haemorrhage into the spinal 

 canal they take the same course as vertebral fractures, and their 

 exact diagnosis is, therefore, of secondary importance. It is otherwise 

 in commotio medullas spinalis, which is generally followed by 

 complete paraplegia. The symptoms due to concussion of the cord 

 may disappear in a few hours, or in eight to fourteen days, and during 



