USES OF BACK-BONE. I? 



8. Uses of the Mode of Structure of the Spinal Column. 



The elastic cushions between the vertebrae make the 

 whole column springy and prevent the transmission of 

 sudden jars along it. By this means the soft brain, car- 

 ried in the skull on its top, and the spinal cord lying in 



FIG. 5. The skeleton of the thorax, with some of the vertebrae of the neck and 

 loins, a, lower neck vertebrae; 6, the first rib; c, the collar-bone; rf, third rib; f, 

 seventh rib; -, last loin-vertebra; A, the breast-bone; /', the shoulder-blade. 



it, are protected from injury in running and jumping. 

 These cushions also allow of a. little bending between 

 each pair of vertebrae, so that the spine as a whole may 

 be bent a good deal. But no sharp bend, such as would 

 nip the spinal cord, which lies inside it, can take place 

 at any one point. 



8. Of what use is the cartilage between the vertebra? in running or 

 jumping? In bending? 



