Chap, xxiv.] THE SPINE. 499 



violent movements to which it may be exposed, render 

 it very liable to be the seat of sprains. These injuries, 

 however, cannot reach any great magnitude, for so 

 closely are the individual vertebrae articulated, that 

 any force severe enough to produce other than slight 

 tearing of the ligaments will tend to cause a fracture 



o O 



or dislocation of the bones. 



Sprains are most commonly met with in the cervical 

 and lumbar segments of the spine. This localisation 

 is due to the mobility of those parts, and to their 

 tendency to diffuse any violence transmitted to them, 

 and so to render it more general. For it is to be noted 

 that the more localised an injury, the more likely it 

 is to produce a fracture or dislocation rather than a 

 sprain. 



In the cervical region, also, the tendency to sprain 

 is increased by the near articulation of the column 

 with the head, and the possibility of any violence 

 applied to the skull being transmitted to the spine. 



Sprains of the spine are not apt to be associated 

 with the external evidences of ecchymosis, since be- 

 tween the skin and the column there intervene not 

 only many layers of muscles, but also dense expan- 

 sions of fascia. 



It has already been pointed out that sprains in the 

 loin, produced by severe bending forwards of the 

 column, may be associated with some damage to the 

 kidney, and consequent haernaturia (page 328). 



A sprained back is often the seat of a considerable 

 degree of pain and stiffness, that persists long after 

 the immediate effects of the lesion must have passed 

 away. Such a condition may be understood by noticing 

 that the column presents a vast number of separate 

 articulations, each provided with cartilage, synovial 

 membrane, and capsular ligaments. These joints have 

 no qualities that exempt them from the common evils 

 incident to sprains of more superficial articulations ; 



