106 ELEMENTS OF HIPPOLOGY. 



CHAPTER VIII. 



THE TRUNK. 



If the legs and neck were removed from the horse's body, the 

 trunk would remain. It is subdivided into the breast, the chest 

 with its enclosing ribs, the back and loins, the abdomen — the 

 cavity in the rear part of the trunk— and its contents, the hips, 

 and the croup. 



The breast is the muscular front portion of the chest, and is 

 bounded by a line connecting the points of both shoulders and 

 by the arm-bone on each side. For saddle purposes, great width 

 of breast is usually at the expense of leaping power and speed, 

 since this width is usually produced by over-development of the 

 shoulder muscles, and not because of increased capacity of 

 the chest. 



The lungs and heart are enclosed, by the ribs and dia- 

 phragm, in the chest. It is by the expansion of the chest that 

 air is brought into the lungs, and by its contraction that air is 

 expelled. This expansion and contraction is performed by the 

 muscles of the ribs. The greater the expansive power of the 

 chest, the greater quantity of air will be drawn into the lungs, 

 and the purifying and vitalizing of the blood will be more com- 

 pletely performed. The ribs should, therefore, be long, convex, 

 and slope to the rear. A horse whose ribs approach close to 

 the haunch-bone is said to be well ribbed up. 



The cavity of the chest is separated from the abdomen by a 

 muscular partition, called the diaphragm. The entire cavity 

 of the chest is lined by a very smooth, well-lubricated membrane, 

 called the pleura, which envelopes, without attaching itself to, 

 the heart and lungs. The abdomen contains the stomach, the 



