Jt 



////: HONKS. 



Tho spinal foramen, which has already assumed a somewhat considerable 

 diameter in the sixth cervical vertebra, is still larger in the seventh. 1 



2. Dorsal Vertebra. 



GENERAL CHARACTERS. In the dorsal vertebras the body is very short, 

 and in front has a largo slightly projecting head ; behind, it lias a shallow 

 cavity. Laterally, these vertebrae present, at the base of the tran.- 

 prooaMtt, four concave articular facets, the two anterior of which arc 

 situated near the head, while the posterior two are hollowed out of the 

 border of the articular cavity of the body. Each of these facets is joiiu >1 t<> 



Fig. 14. 



an analogous facet on the neighboui-in^ \vr- 

 tcbra to form a small excavation, into which 

 is received the head of the corresponding 

 rib. The spinous process is very high, is 

 compressed on both sides, inclines backwards, 

 and its summit is terminated by a tubercle. 

 The transverse processes are unitubercular, 

 and directed obliquely outwards and up- 

 wards ; on their external aspect they have a 

 diarthrodial plane facet which corresponds 

 to the tuberosity of the rib. The nrt'n-nlr 

 processes are narrow, and constitute simple 

 unrelieved facets cut on the base of the 

 spinous process. The posterior notches are 

 deep, and sometimes converted into foramina. 

 SPECIFIC CHARACTERS. None of the 

 eighteen dorsal vertebrae differ much from 

 the type just described ; and it is difficult 

 to establish special characters for each. 

 It is, nevertheless, possible to assign to a 

 1, Body; 2, 2, Articular facets for the dorsal vertebra, approximately, the rank it 

 head of rib; 3, Articular facet for should occupy, in accepting the following 



tuberosity of the rib; 4, Articular factg ag a guide ._]__ The veli j cal diameter 



processes; 5, Spinal foramen; b, /. .1 Ztj. t m. j 



Tuberous base of spmous process \ f tho rcrfc&mZ bodies augments progres- 



7, Posterior articular face of body; sively from before to behind. Their lateral 



8, 8, Transverse processes; 9, diameter, which determines that of the spinal 

 Superior spinous process; 10, An- canal, becomes, on the contrary, less from the 



first to the tenth vertebra; after which it 



assumes increasing proportions to the last one. The articular surfaces, which 

 serve for the mutual contact of head and cavity, become larger and shallower 

 in proportion as the vertebrae are more posterior. The inferior spine on the 

 body is very salient and tuberculous in the two first vertebra), very acute in 

 the third and fourth ; it disappears in the sixth and ninth, to re-appear and 

 become more marked from the tenth to the last. 2. The int<'rn>rtebral cavitirx, 

 intended for the reception of the heads of the ribs, diminish in depth and 

 extent from the first to the last. 3. Tho longest spinous process l>el< >n^s t<> the 

 third, fourth, and fifth vertebra) ; those which follow gradually decrcu.- 

 the eighteenth. Their width diminishes from the second to the eighth ; it 

 afterwards increases in a progressive manner in the succeeding vertebra) ; 



TVPE OF A DORSAL VERTF.IlRA : 

 T1IK FOURTH. 





1 M. Goubaux hns sometimes mot willi asymmetrical cervical vi rtdira- ; certain 

 vertebrae, tricuspid on one side, arc only bicuspid or imicupid on tho ojijxwitt! bide. 



