STRUCTURE AND ECONOMY OF THE FOOT. 



305 



both in front and behind. The compact and solid structure of 

 the pasterns, and the irregular surface and porous nature of the 

 coffin bone are exhibited, but may be better understood by a;i 

 examination of the bones themselves. 



Fig. 3. Front View of the Bones of the 

 Foot and Pastern. 



b. The large pastern or os sufTraginis. 



c. The sinall pastern or os corona?. 



d. The coffin bone, or os pedis, showing 

 its perforated and irregular surface. 



Fig. 4. Back Vieio of the Bones of the 

 Foot and Pastern, 



a a. The sesamoid bones. 



b, Tlie large pastern. 



c, The small pastern. 



d, '1 he coffin bone, showing its lower 

 surface with the holes for the passage 

 of the arteries to the centre of the bone, 



e, The navicular bone. 



The bottom of the horny foot is shown in fig. 1., page 309., 

 where the sole, bars, and frog of a good-shaped foot in a natural 

 unpared state are shown. 



The lower part of the foot is shown by fig. 2., p. 304., the horny 

 parts being removed, so as to exhibit the sensible sole, frog, and 

 bars, the shape of which correspond exactly with their horny 

 coverings. The parts, though largely supplied with blood, are 

 yet not so vascular as the laminaj. 



Fig. 5., p. 306., principally shows the singular manner in which 

 one flexor tendon forms a sheath for another, thus permitting the 

 very great extent of motion these parts possess, without any 

 diminution of strength. The sheath thus formed is lubricated 

 with synovia, and thus any penetration or injury of the sheath is 

 a matter of great consequence, quite as much indeed, as that of 

 a joint, for inflammation of the most violent degree is likely to 



