BROKEN BACK. 121 



but tLe muscular force remains in spite of all the tying down 

 that can be done with ropes^ and bones will as surely be 

 broken. 



I have always held the opinion now laid down ; and although 

 it might have been shaken during my fii-st college days, it 

 returned to me with greater force from seeing a horse break 

 his back while tied down with the back rope. Wlien I first 

 promulgated this idea, during my first course of lectures at the, 

 Edinburgh Yeterinary College, the majority of the senior stu- 

 dents thought my teaching absurd ; and to prove it so one of 

 them purchased a subject for dissection, and before destroying 

 him, had him cast for the instruction of his fellow-students, 

 and secured so firmly that he could not break his back, as ha 

 said ; but, wonderful to relate, the animal tried to struggle, the 

 back was broken, and he rose no more. 



It is a general belief among veterinarians that a horse with a 

 broken back cannot move his tail ; but this is liable to excep- 

 tions, and it will be found that complete paralysis from fracture 

 will be accompanied at first by movements of the taih To take 

 this symptom as being diagnostic of fracture, and to conclude 

 tliat when movement of the tail remains, the injury is a sprain 

 of the psoaa muscles, may lead to error and wrong prognosis. 

 Absence of sensibility and the history of the case are much 

 more to be depended upon. 



As a rule, but not without exception, vertebrae are fractured 

 through their bodies, the arches remaining intact. 



TRACTURES OF THE OS SACRUM. 



The anterior portion of the border of this bone is sometimes 

 fractured by violent falls, or by the animal becoming " cast in 

 the stall" It will be remembered that the sides of the os 

 sacrum are attached to, and situated below, the posterior spinous 

 process of the ilium, giving support and attachment to the 

 pelvis, and connecting it with the vertebra. When it 'is frac- 

 tured, the iliac spine, losing its support, immediately falls, and 

 the highest part of the quarter becomes flattened, which can 

 be easily seen by comparison with its fellow of the other side. 

 Examination per rectum will enable the practitioner easily tp 

 diagnose the exact seat of the injury. I'rofessor Dick used to. 



