40 



ANATOMY FOR NURSES. 



[ClIAP. IV. 



A 



rotates when the head is turned from side to side, carrying the 



skull, to which it is firmly articulated, 

 with it. The bodies of the dorsal ver- 

 tebrae are larger and stronger than 

 those of the cervical; they contain 

 depressions for the reception of the 

 vertebral ends of the ribs. The bodies 

 of the lumbar vertebrae are the largest 

 and heaviest in the whole spine. The 

 sacrum, formed by the union of the 

 five sacral vertebrae, is a large trian- 

 gular bone situated like a wedge 

 between the ossa innominata ; it is 

 curved upon itself in such a way as 

 to give increased capacity to the pel- 

 vic cavity (vide Fig. 46). The coccyx 

 (cuckoo's bill) is usually formed of 

 four small segments of bone, and is 

 the most rudimentary part of the 

 vertebral column. 



The vertebral column as a whole. 

 The spinal column in a man of aver- 

 age height is about twenty-eight 

 inches long. Viewed from the side 

 it presents four curvatures ; one, with 

 the convexity forwards in the cervi- 

 cal region, is followed in the dorsal, 

 by a curve with its concavity towards 

 the chest. In the lumbar region the 

 curve has again its convexity for- 

 wards, while in the sacral and coccy- 

 geal regions the concavity is turned 

 inwards. These curvatures confer a 

 considerable amount of springiness 

 FIG. 42. -SIDE VIEW OF SPI- upon t ^ e gpinal co l umn wn i c h would 



NAL COLUMN, WITHOUT SACRUM L 



AND COCCYX, i to 7, Cervical be lacking were it a straight column : 



vertebn,; s t in dorsal verte- th elasticity is further increased by 



brae ; 20 to 24, lumbar vertebrae ; J 



A, A, spin.. us processes; c, D, the disks of fibro-cartilage lying be- 

 axis. the vertebrae. These disks or pads 



