556* SURGICAL APPLIED ANATOMY, [cw xxiv. 



Points of Origin from the Cord. 



The first cervical nerve arises from the cord opposite the 



interval between the atlas and occiput. 

 The second and third cervical nerves arise from the cord 



opposite the axis. 

 The fourth, fifth, sixth, seventh, and eighth cervical nerves 



arise from the cord opposite the third, fourth, fifth, sixth, 



and seventh vertebra? respectively. 

 The first four dorsal nerves arise from the cord opposite the 



discs below the seventh cervical and the first, second, and 



third dorsal vertebra respectively. 

 The fifth and sixth dorsal nerves arise from the cord opposite 



the lower borders of the fourth and filth vertebrae. 

 The remaining six dorsal nerves arise from the cord opposite 



the bodies of the sixth, seventh, eighth, ninth, tenth, and 



eleventh vertebrae. 

 The first three lumbar nerves arise from the cord opposite the 



twelfth dorsal vertebra. 

 The fourth lumbar nerve arises from the cord opposite the disc 



between the twelfth dorsal and first lumbar vertebra?. 

 The last lumbar nerve, together with the sacral and coccygeal 



nerves, arise from the cord opposite the first lumbar 



vertebra. 



It will be seen, therefore, that in taking note of 

 the symptoms due to crushing the entire nerve con- 

 tents of the vertebral canal at a certain spot, con- 

 sideration must be taken, not only of the effects of 

 damaging the medulla at that point, but also of the 

 result of lacerating nerve trunks that may issue there, 

 although their origins are above the seat of lesion. 

 The cord is also very often only damaged in part, or 

 it may entirely escape, while one or more nerves are 

 crushed by the fractured vertebrae, or by fragments of 

 bone separated by the lesion. 



In fracture-dislocations the upper vertebral body, 

 as already stated, usually glides forwards, with the 

 result that the anterior and antero-lateral parts of the 

 cord are brought into violent contact with the pro- 

 tecting border of the vertebrae below the seat of lesion. 



