THE FOOT. 



291 



I 



Tig. 12 — section of the parts entering into the composition of the foot and the 

 fetlock and pastern joints. 



H. Cleft of frog. 



A. Os sufiFraginis. 



B. Os coronae. 



C. Os pedis. 



D. Os naviculare. 



E. E. The perforans and perforatus tendons. 

 Q. Inferior sesanioideal ligament. 



I. Side of frog cleft. 



J. Sole. 



K. Crust. 



L. Coronary substance. 



there is no room for any swelling (the invariable accompaniment 

 of that disease), and intense pain is occasioned, as well as rapid 

 disorganization of the structure itself. The horny case is 

 attached to the foot by a delicate membrane, which lies in folds 

 upon the pedal bone, and it can be torn away by violence, or when 

 putrefaction has commenced, with great ease. These parts are 

 beparately displayed. The several parts which we shall have to 

 examine, commencing from without, are — 1. The horny case or 

 hoof; 2. The parts which secrete it ; 3. The arteries which supply 

 it with blood ; and 4. The pedal bone and cartilages, as well as 

 the navicular bone, which it encases. 



The hoof consists of three distinct parts, which, though in the 

 recent state they are inseparably united, may be readily separated 

 after maceration for a few days. These are the external wall or 

 crust, the sole or slightly concave surface forming the bottom or 

 floor of the case, and the triangular central portion of this called 

 the frog. The crust reaches from the edge of the hairy skin to 

 the ground, and averages about three inches and a half in depth. 



