DORSAL VERTEBRA. 449 



long spinous process, which projects beyond all the rest 

 and is readily felt beneath the skin, ends in a tubercle 

 and is not bifurcated, and gives attachment to the liga- 

 mentum nuchae. Its transverse processes have no foramina, 

 or if there be any, they are small and transmit only a vein. 



PECULIARITIES OF DEVELOPMENT IN THE CERVICAL VERTEBRA. 



The atlas, instead of the usual three primary ossific cen- 

 tres, is seen to have four and sometime's five ; one for each 

 lateral portion, one, occasionally two, for the anterior arch, 

 and one for the centre of the posterior arch. The lateral 

 centres unite with the posterior centre during the second 

 and third years, and with the anterior about the fifth or 

 sixth year. The axis is found with five centres of ossifica- 

 tion, two for the odontoid process, one, sometimes two, for 

 the body, and one for each lateral part. The body and 

 odontoid process begin ossifying about the sixth month, and 

 are found united about the third or fourth year. The lat- 

 eral portions unite soon after birth, and join the body 

 about the fourth or fifth year. 



The seventh cervical vertebra is found to have the anterior 

 portion of its transverse process frequently presenting a 

 separate osseous centre about the second or sixth month, 

 which unites with the body about the fifth or sixth year. 

 Separate ossific centres have also been noticed in the trans- 

 verse processes of the second, fifth and sixth cervical verte- 

 bra?, and also the first lumbar. 



DORSAL VERTEBRAE COMMON CHARACTERISTICS. (Fig. 128.) 



The dorsal vertebras occupy an intermediate position be- 

 tween the cervical and lumbar, and are also intermediate 

 in size; they become less and less from the first to the third 

 or fourth, and then increase to the last. The body is thicker 

 behind than before, and more cylindroid than those of the 

 neck ; the upper and lower surfaces at the posterior edge, 

 near the origin of the lateral processes, present two small 

 articular facets for receiving one half of the head of each 

 rib the adjoining vertebra having a corresponding de- 

 29 



