40 SCIENTIFIC HORSESHOEIXG. 



The ligaments binding this joint. 3. The terminations of the 

 tendons that flex and extend the foot from their insertions in tlie 

 coffin-bone. 4. The soft structures of the foot. 5. The sen- 

 sitive structures, including the vessels and nerves of this region. 



Bones of the Foot. — In addition to the foregoing, it is 

 customary to include in each complete digit the ankle, and 

 fetlock, as constituting the apparent foot of a horse. The 

 bones of this re2:i<»n are then divided into three sections — 

 reckoning from above to below — placed end to end one upon 

 another, which are termed the phalanges. The first com- 

 prises the large or upper pastern-bone and the two sesa- 

 moids, which unite with the lower head of the cannon-bone 

 in forming the pastern-joint. The second phalanx is composed 

 of the small or lower pastern and by its contact with the upper 

 pastern makes the pastern-joint. The third and last phalanx, 

 terminating the limb, consists of the pedal- or coffin-bone and 

 the navicular-bone, which unite with the lower end of the small 

 pastern in forming the pedal- or coffin-joint. These bones are 

 situated in an oblique direction downward and forward, and 

 form the extremity of the digit upon which tlie soft structures 

 of the foot are built, as shown in Fig. 3 and 5. 



The Pedal- or Coffin-bone. — The third phalanx of the foot 

 has, from the earliest times, most occupied the attention of 

 observers, owing to its greater liability than any bone of the 

 extremities to injury from casualties natural to its peculiar situa- 

 tion and uses. It is the base upon which the entire foot is 

 constructed, sustaining the hoof tliat incloses it as it fixes itself on 

 the ground, and acting as the point of leverage in receiving 

 and applying the power involved in the movement of the limb. 

 It is a ver}^ hard bone, very finely poroused with numerous 

 perforations and channels for the penetration of blood-vessels 

 and nerves supplying the enveloping tissues. Its lower bor- 



