466 
INJURIES TO THE VERTEBRAE. 
In horses, the condition is oftenest mistaken for hemoglobinuria. The 
history generally clears up this point, otherwise the urine must be 
examined, though it should not be forgotten that in hemoglobinuria 
the urine occasionally appears normal; the presence of blood, colouring 
matter, or albumen would, however, point to the latter disease. In 
hemoglobinuria the muscles are abnormally hard and firm, especially 
in the dorsal region, but in pressure paralysis there is pronounced 
relaxation. Again, in hemoglobinuria the visible mucous membranes 
are more or less reddened, which, during the early stages at least of 
fracture of the vertebre, is certainly not the case. Diagnosis is more 
difficult if the animal is unable to rise, and is suffering from fever. 
Plugging of the posterior aorta or of the iliac arteries produces similar 
symptoms, but, at first, is usually accompanied by clonic and tonic con¬ 
tractions ; at a later stage, the interference with movement occurs 
gradually, and is only seen 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 ruptured, or bleeding into the vertebral canal may 
be produced, without the vertebrae being displaced ; finally, concussion 
of the medulla may exist without visible lesions or anatomical changes, 
a condition clinically described as commotio medullae 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 vertebral canal they take the same course as vertebral fractures, and 
their exact diagnosis is, therefore, of no especial importance. It is other¬ 
wise in commotio medullae spinalis, which is generally followed by 
symptoms of complete paraplegia, but disappears again in a short time, 
sometimes even within a few hours. In many cases, therefore, the 
diagnosis must be extremely cautious, and an expectant attitude should be 
assumed. The symptoms due to concussion of the cord may disappear 
in eight to fourteen days, and during this time recovery is not out of 
the question. It should be borne in mind that concussion of this kind 
is rare in the horse, but fairly frequent in small animals like dogs and 
cats. 
Schmaus’s observations and experiments show that in concussion of 
the cord, bleeding, softening, swelling, and degeneration of single axis- 
cylinders occur. It is evident that the course of such injuries depends 
on the kind and extent of the anatomical changes; and as these cannot 
be exactly defined during life, prognosis is always doubtful. 
In fracture of the vertebra the last hope of recovery vanishes as soon 
as paraplegia is complete. Provided the animals can stand, treatment 
