THE DORSAL VERTEBRA. 



of vertebra prominens has been 

 given to this bone. The transverse 

 processes are massive, and only 

 slightly grooved, with a small fora- 

 men ; their posterior tubercle is 

 large and prominent, while the 

 anterior is but faintly marked. 



In most cases the spinous process of 

 the sixth cervical vertebra is also un- 

 divided ; and in the dark races of man 

 the spinous processes of the third, fourth 

 and fifth vertebrae are more frequently 

 simple than bifid. (D. J. Cunningham, 

 Journ. Anat., xx, 637.) 



Dorsal or thoracic vertebrae. 



These are twelve in number, and 

 support the ribs. 



The lody as seen from above is 

 somewhat heart-shaped ; its antero- 

 posterior and transverse diameters 

 are nearly equal ; its depth is greater 

 behind than before. 



It is specially characterized by 

 the presence, at the place where it 

 joins the arch, of articular surfaces 

 for the heads of ribs. In the greater 

 number of instances there are two 

 costal surfaces on each side, one at 

 the upper, the other at the lower 

 border, so 'placed that each com- 

 pletes, with that of the adjacent 

 vertebra, a cavity for the head of 

 one rib. 



The lamince, broad and flat, are 

 imbricated or sloped one pair over 

 another like tiles on a roof. The 

 superior notches are very shallow, 

 the inferior deep. 



The spinous process, described as 

 bayonet-shaped, is three-sided, and 

 terminates in a slight tubercle. It 

 is longest and has the greatest 

 downward inclination in those to- 

 ward the middle of the series. 



The transverse processes are 

 strong, directed outwards and back- 

 wards, and terminate in a rough 



knob which presents anteriorly a smooth surface for articulation with the tuberosity 

 of a rib. 



The articular processes have their cartilaginous surfaces nearly vertical. Those 

 of the superior processes look backwards, slightly upwards and outwards ; those of 

 the inferior look forwards, slightly downwards and inwards. 



Fig. 7. SIXTH DORSAL VERTEBRA : A, FROM 



ABOVE ; B, FROM THE BIGHT SIUK. 



(Drawn by D. Gunn. ) 



Fig. 8. FIRST DORSAL VERTEBRA, FROM THE RIGHT 

 SIDE. (Drawn by D. Gunn.) 



