14 THE ARTISTIC ANATOMY OF ANIMALS 



dorsal and the great oblique of the abdomen, we find a large 

 space, in which the ribs, with the intercostals which join them, 

 are uncovered ; the muscles in question separate the one 

 from the other, under the influence, it would seem, of the 

 great dimensions of the lateral wall of the thorax. 



The Sternum. — The sternum is, in quadrupeds, directed 

 obliquely downwards and backwards ; its form varies in 

 different species. In the carnivora, it consists of eight bones. 



Fig. 6. — A Vertical Section of the Thorax of a Quadrux'Eu 



(Diagrammatic). 



I, Fifth dorsal vertebra ; 2, sternal region; 3, costal region of one side; 

 3', costal region of the opposite side. 



irregularly cylindrical in form, being slightly flattened from 

 within outwards, and thickened at their extremities. They 

 remain separate, and this contributes elasticity and flexibility 

 to the thorax. The first nine costal cartilages articulate 

 directly with the sternum. The first of these cartilages 

 articulates with a nodule situated a little above the middle 

 of the first bone of the sternum. 



In the horse the sternum is flattened laterally in its 

 anterior portion, and from above downwards in its posterior 



