58 OSTEOLOGY OF THE HORSE. 



The posterior surface is slightly excavated, and is free from 

 asperities. Superiorly, it presents a smooth lip of bone, between 

 which and the flexor tendon exists a bursal connexion. 



The inferior surface, like the superior, is entirely articulatory : 

 it closely resembles that of the pastern bone, only it is rather 

 broader. In outline, it has the figure of a painted heart, whose 

 apex is curved forward aud upward : basis, backward and up- 

 ward. It is bi-convex from before backward, consisting of two 

 condyloid prominences, parted by a shallow transverse depression. 

 It is adapted to a counterpart articulatory formation of the coffin 

 bone. 



Connexion — With the pastern, coffin, and navicular b^ones. 



OF THE FOOT. 



The foot, or third phalanx, forms the resting, bearing, or ter- 

 minating part of the limb. The coffin bone constitutes its osseous 

 fabric ; to which the navicular may be regarded as an appendage. 



THE COFFIN BONE. (OS PEDIS.) 



Situated within the hoof, which it nearly resembles in 



/o/7w— Being in its outline semi-lunar: anteriorly and superi- 

 orly, convex ; posteriorly and inferiorly, concave. Its shape, how- 

 ever, varies with the natural make and morbid changes in the 

 form of the hoof. 



Division — Into wall, sole, tendinous surface, articulatory sur- 

 face, and wings. 



The wall is the semicircular prominent part in front, and 

 corresponds to the wall or crust of the hoof. It is convex — most 

 so, anteriorly ; it possesses a certain degree of declivity, which 

 increases in degree, but decreases in extent, as we proceed from 

 the front to the sides, the greatest elevation, as well as slant, of 

 the wall presenting anteriorly ; and it exhibits everywhere a fur- 

 rowed and porous surface; the furrows, which run from above 

 downwards, being most distinct inferiorly and laterally ; and the 

 holes or pores consisting of a large and small set, of which the 

 large only are numerable or worthy of particular notice, the small 

 ones being infinite, and numbers of them even imperceptible. The 

 foramina (for the large are alone worthy of the name, the small 

 being simply porosities) are regularly disposed in so far that we 

 invariably find several of them ranged at nearly equal distances 

 around the circumference of the wall, a little above its edge; and 

 two others at or near the terminations of two grooves, which come 

 from the wings, and run along the sides of the wall : five or six 

 others also are commonly seen within the intermediate space, 

 between the two latter. Through the foramina pass blood-vessels 



