D ORSA L VER TEBR^E. 



39 



info-vertebral notches are very shallow, and lie behind the articular processes : the 

 inferior in front of them, as in the other cervical vertebrae. The apinous process 

 is of large size, very strong, deeply channelled on its under surface, and presents 

 a bifid, tubercular extremity for the attachment of muscles which serve to rotate 

 the head upon the spine. 



Seventh Cervical (Fig. 4). The most distinctive character of this vertebra 

 is the existence of a very long and prominent spinous process ; hence the name 

 ' vertebra prominens." This process is thick, nearly horizontal in direction, not 

 bifurcated, and has attached to it the lower end of the ligamentum nuchae. The 

 transverse process is usually of large size, its posterior tubercles are large and 

 prominent, while the anterior are small and faintly marked ; its upper surface has 

 usually a shallow groove, and it seldom presents more than a trace of bifurcation 

 at its extremity. The foramen in the transverse process is sometimes as large as 

 in the other cervical vertebrae, but is usually smaller on one or both sides, and 

 sometimes wanting. On the left side it occasionally gives passage to the vertebral 

 artery ; more frequently the vertebral vein traverses it on both sides ; but the 

 usual arrangement is for both artery and vein to pass in front of the transverse 

 process, and not through the foramen. Occasionally the anterior root of the 

 transverse process exists as a separate bone, and attains a large size. It is then 

 known as a " cervical rib." 



Characters of the Dorsal Vertebra. 



The Dorsal Vertebrae are intermediate in size between those in the cervical and 

 those in the lumbar region, and increase in size from above downward, the upper 



Superior articular process. 



Demi-facet for head of rib. 



Facet for tubercle of rib. 



Demi-facet for head of rib. 

 Inferior articular process. 



FIG. 5. A dorsal vertebra. 



vertebras in this segment of the spine being much smaller than those in the lower 

 part of the region. The dorsal vertebrae may be at once recognized by the pres- 

 ence on the sides of the body of one or more*facets or half-facets for the heads of 

 the ribs. 



The bodies of the dorsal vertebrae resemble those in the cervical and lumbar 

 regions at the respective ends of this portion of the spine ; but in the middle of 

 the dorsal region their form is very characteristic, being heart-shaped, and as 

 broad in the antero-posterior as in the lateral direction. They are thicker behind 

 than in front, flat above and below, convex and prominent in front, deeply concave 

 behind, slightly constricted in front and at the sides, and marked on each side, 



