24 DESCRIPTION OF THE SKELETON. 



large articulating surfaces for the first rib. The transverse processes of 

 this vertebra are large, thick, and rough ; they have no perforation for the 

 vertebral artery. The spinous process is double the length of the sixth, 

 being six and a half inches long. The spinal canal has an oval form in 

 the cervical vertebrae, and is about four inches from above downwards, but 

 less than that in the transverse direction. 

 Dorsal Dorsal Vertebrae. — The dorsal vertebra? are twenty in number. 



Vertebrae. 



They form a considerable concavity; for, springing from the base formed 

 by the cervical vertebrae, they gradually ascend to about the twelfth, and 

 then descend to the lumbar vertebrae, which are continued downwards to 

 the pelvis ; so that the dorsal and lumbar vertebrae, taken together, form 

 an arch, the concavity of which is downwards. The central point of the 

 segment of the circle thus formed is more than a foot higher than its 

 extremities. The inferior surface of this part of the spinal column is gene- 

 rally rounded ; but, as it approaches the lumbar vertebrae, it becomes less 

 convex. The superior face of the column presents three lines; the middle 

 formed by the projections of the spinous, and the two lateral by those of 

 the transverse processes. 



The first seven dorsal vertebrae are remarkable for very long spinous 

 processes ; from the fourth to the sixteenth, these diminish in length (Plate 

 XXII.) ; the remaining four are equal. The extremities of the spinous 

 processes of the anterior dorsal vertebrae are much enlarged and scabrous 

 for muscular and ligamentous attachments ; all of them have a roughness 

 at their extremities. The third of these measures eight inches from before 

 backwards ; and the fourth, seven inches transversely. The longest spinous 

 process, that of the third dorsal, is twenty-three and a half inches long ; 

 the last, which is the shortest, is only four inches in length. The tips of 



