VEETBBRAL COLUMN 



125 



FIG. 83. 



MALFORMATION OF VERTEBRAE. 



A malformation may be confined to one vertebra, the result 

 usually of a failure of the parts to unite, as in the case illustrated 

 (Fig. 83), where the halves of the spinous process 

 still remain distinct. A malformation may involve 

 two or more vertebrae and be due to a dislocation 

 during development of the centres of ossification. 

 In the specimen of the second thoracic vertebra 

 shown in Fig. 84 the body appears to be normal, 

 except for the union with it of the right half- 

 body of the next vertebra; its neural arch, how- ABNORMAL VERTEBRA . 

 ever, is completed on the right side by half the 

 neural arch of the next vertebra ; its own half neural arch is distinct 

 and terminates in a smaller right spinous process ; this half neural 

 arch is recognized as belonging to this vertebra, and not to the ver- 



FIG. 84. 



Right Spinous Process. 



Spinous Process. 



Entire ( ' 

 Facet. 



Intervertebral Foramen. 

 CEPHALIC ASPECT. 



Right Half-body. 



VENTRAL ASPECT. 



ABNORMAL THORACIC VERTEBRA. 



tebra immediately preceding, because the features on its transverse 

 process are similar to the features on the single left transverse process. 



HUMAN VERTEBRAL COLUMN. 



The vertebral column occupies a vertical position in the human 

 body ; hence in most works on anatomy the terms superior and inferior 

 are used instead of cephalic and caudal, and anterior and posterior 

 instead of dorsal and ventral. The student will find no difficulty in 

 changing from one set of names to the other. 



When we compare the human vertebral column (Figs. 6, 85) with 

 that of the cat, we observe that it is relatively much shorter ; it 



