12 THE ARTISTIC ANATOMY OF ANIMALS 



The dorsal and lumbar regions are placed in a single curved 

 line, more or less conca.ve downwards ; so that in the lumbar 

 region there is no curve analogous to that which exists in 

 man ; a form which, in the latter, is due to the biped atti- 

 tude — that is to say, the vertical position of the trunk. 

 Briefly, there is in quadrupeds one dorso-lumbar curve ; and 

 not both a dorsal and a lumbar, with convexities in opposite 

 directions. 



At the extremity of the dorso-lumbar region is the 

 sacrum and the caudal appendix, which describe a curve 

 of which the concavit}^ is directed downwards and forwards. 



It is necessary to point out that it is not the curves of the 

 three anterior portions of the spinal column which deter- 

 mine the form of the superior border of the neck and 

 shoulders, and of the same part of the trunk. For the first 

 portion, there is a ligament which surmounts the cervical 

 region, and substitutes its modelling influence for that of the 

 vertebrae. It is the superior cervical ligament, which arises 

 from the spinous process of the first cervical vertebrae, and is 

 inserted into the external occipital protuberance on the 

 upper part of the posterior surface of the skull. The summits 

 of the spinous processes of the vertebrae alone give form to 

 the superior median border of the trunk. In this connection 

 we here repeat that it is not the general curvature of the 

 vertebral column which produces the withers, but the great 

 length of the ^spinous process of the first vertebrce of the 

 dorsal region. 



The Thorax 



1^ The dorsal vertebrae form the posterior limit in man, and 

 superior in quadrupeds, of the region of the trunk known 

 as the thorax. A single bone, the sternum, is situated at 

 the aspect opposite ; the ribs bound the thorax on its sides. 

 In its general outlines the thorax in quadrupeds resembles 

 that of man — that is to say, that, as in the latter, the anterior 

 portion — superior in the huma.n being — is narrower than the 

 part opposite. But the progressive widening takes place in 

 a more regular and continuous fashion, so that it presents 



