CHAP, iv.] CERVICAL VERTEBRA. 33 



very late in making their appearance, and not joined until 

 long after the rest of the vertebra is completed. A small 

 epiphysis is also formed on the end of the spinous 

 process. 



Lastly, the inferior or ventral bar of the transverse process 

 of the seventh vertebra is developed from a separate centre 

 of ossification, and occasionally the same part of the sixth 

 and fifth has its own separate nucleus. This bar of bone is 

 connected internally with a projection from the side of the 

 body, ossified from the arch ; externally with the end of the 

 upper or true transverse process, which is an exogenous 



FIG. 8. Sixth cervical vertebra of a child, i. c centrum ; ncs neuro-central suture ; 

 v vertebrarterial canal ; az anterior zygapophysis. 



growth from the arch, so that it is attached to the vertebra 

 entirely above the neuro-central suture. Occasionally it 

 acquires an abnormal development, and grows into a con- 

 siderable rib-like bone, in which case it is usually united at 

 its distal extremity with the first thoracic rib. 



The first vertebra or atlas (Fig. 9) is little more than an 

 oval ring, thickened on each side into the so-called " lateral 

 mass/' which bears an articular surface before and behind. 

 The anterior surfaces are very large, elongated from above 

 downwards, and hollowed for the reception of the condyles of 

 the occiput. The posterior articular surfaces are subcircular 



D 



