546 SURGICAL APPLIED ANATOMY. .{Chap. xxiv. 



compression, while its posterior parts, composed of 

 slighter and more compact bones and surrounded by 

 many strong ligaments, are well arranged to resist the 

 effects of a tearing force. The spinal cord, situated 

 between these two divisions, occupies the position of 

 least danger. 



The vertebrae may be fiactured without being dis- 

 located, but a dislocation without a fracture is rarely 

 possible. 



It would appear, indeed, that a luxation of the 

 spine, with no fracture of bone, cannot occur in either 

 the dorsal or lumbar regions. Mr. Jacobson, in the 

 essay above referred to, writes, " \ believe I am correct 

 in stating that there is no case recorded, and thoroughly 

 ^verified, in recent years, of dislocation of the lumbar 

 or dorsal vertebi-se, unaccompanied with any fracture 

 of the body, transverse or articular processes." Dislo- 

 cation without fracture has been met with in the 

 cervical spine, although even there, if we except 

 the first two vertebrae, it is very rare. When it 

 occurs it most often involves the fifth vertebra, which, 

 with the rest of the column above it, is displaced for- 

 wards and downwards. Luxations in other directions 

 have been noted, but they are extremely uncommon. 

 The possibility of luxation in the cervical region with- 

 out dislocation is explained by the small size of the 

 vertebral bodies, the obliquity of their articular pro- 

 cesses, and the relatively slight opposition they offer 

 to displacement when compared with like processes in 

 the other parts of the column. The luxation is usually 

 bilateral and incomplete, and the result of a forcible 

 bending of the head and upper part of the spine for- 

 wards and downwards. When situated high up the 

 displacement may be appreciated by an examination 

 of the part through the pharynx. In the complete 

 bilateral dislocation the cord is usually hopelessly 

 crushed. These luxations have seen reduced by forcible 



