FKACTUBES OF THE SPINE. Ill 



FRACTURES OF THE SPINE. 



Fractures of the vertebrae may occur without dislocation, 

 although it is rare for a dislocation to occur without an accom- 

 panying fracture, owing to the intricate manner in which 

 vertebras are articulated together. In the dorsal region particu- 

 larly the spinous processes may be broken off, or the laminae 

 driven towards the spinal cord without displacement of the rest 

 of the bone. This lesion occurs as a rule from direct violence. 

 The enclosed spinal cord is liable to injury either by pressure 

 from the fragments of bone themselves, or from the extravasated 

 blood, which may be found either without or within the thecal 

 sheath. 



Fracture-dislocation occurs most usually at the more flexible 

 parts of the spine. Hence it is commonly seen at the lower 

 cervical and dor si- lumbar regions. As a rale indirect violence 

 induces the lesion, the fracture often involving both the centrum 

 and the neural arch as the result of the sudden and forcible 

 wrenching of one centrum from another. The spinal cord 

 lying in the vertebral canal will almost certainly be acutely 

 bent and pressed upon by the dislocated bones. In the case of 

 dislocation of the body of the upper vertebra forwards and down- 

 wards, it is the posterior superior edge of the lower vertebra 

 which causes the mischief to the cord. On the other hand, when 

 the body of the upper vertebra is dislocated backwards, often 

 with crushing and fracture of the neural arches involved, it is 

 the lower and posterior edge of this upper centrum which presses 

 upon the spinal cord. 



Most of the symptoms are referable to the damage done to the 

 cord itself. As a rule injury to the cord is not recovered from in 

 that there is no power of regeneration, at any rate so far as the 

 grey matter is concerned. It therefore follows that even if death 

 does not take place, restoration of function is very unlikely. 



Owing to the fact that the area over which the cord is involved 

 extends some little distance above the actual site of the fracture- 

 dislocation, it will be evident that the peripheral signs will not 



