MANUAL FOR STABLE SERGEANTS. 47 



laminae of the wall they support the weight of the body within the 

 hoof. 



(d) The corium of the sole (sensitive sole) (figs. 19, 23) corresponds 

 to the horny sole, to which is supplies nutrition. 



(e) The corium of the frog (sensitive frog) (fig. 23) is molded on the 

 upper surface of the frog and is attached to the under surface of the 

 digital cushion. It nourishes the frog. 



THE HOOF. 



115. The hoof is the horny covering of the foot. It is divided 

 into three parts, the wall, sole, and frog. 



(a) The ivall is that part of the hoof which is visible when the foot 

 is placed on the ground. It covers the front and sides of the foot, 

 and is bent abruptly inward and forward at the heels to form the 

 bars. The latter appear on the bottom of the foot as horny ridges 

 which extend forward and inward toward the point of the frog. 

 The bars secure a solid bearing for the back part of the foot; they 

 give additional strength to the hoof, and, being a part of the wall, 

 are intended to bear weight. For convenience in study the wall 

 may be divided into three parts, the toe, quarters, and heels. 



The toe is the front part of the wall. 



The quarters, one on either side, extend backward from the toe 

 to the heels. 



The heels are the hindermost part of the foot. They are located at 

 the point where the wall bends inward to become the bars. 



The external surface is smooth, and its upper portion is covered 

 with a thin layer of soft horn called the periople. Extending from 

 the periople to the bottom of the foot is a thin layer of horny scales 

 which gives the surface of the wall its smooth, glossy appearance. 



The internal surface is-concave from side to side, and presents about 

 600 thin, white, parallel plates of horn called laminae, which extend 

 from the coronary groove to the bottom of the wall. These homy 

 laminae dovetail with the corresponding laminae of the corium and 

 bind the wall of the hoof to the third phalanx and the greater part 

 of its cartilages. 



The upper or coronary border is thin, and its outer surface is covered 

 by the periople. The inner side of this border is hollowed out to 

 form the coronary groove, which extends all the way round the top 

 of the wall and contains the thick coronary corium. 



106233°— 17 4 



