THE SKELETON. 33 



long and the metacarpus short, whilst in the horse we find the 

 latter bones long, and the former comparatively short. 



The bones below the fetlock, the Phalanges, which in carni- 

 vorous animals are in four divisions, in the horse are consolidated 

 into one. Thus we have the first, second, and third phalange, 

 witli a supplementary bone, called the navicular, or shuttle bone. 



The first phalange is called tlie Os Suffragbiis, or large jmstem, 

 which receives the lower extremity of the cannon on its upper 

 surface, having depressions corresponding to the convexities of 

 the cannon, thus forming the /e^/oc/^ joint. Immediately behind 

 the fetlock joint, and indeed entering into its composition, are 

 two small triangular bones, called the sesamoids. They are sus- 

 pended from above by a very strong ligament, and thus, besides 

 protecting the fetlock joint, are the means of aifording an im- 

 portant spring to the animal. Tiie large pastern rests entirely 

 on the small pastern, a shorter but sti-onger and thicker bone 

 than the former ; thus forming the jiastern joint, the frequent 

 seat of those bony tumours called ringbones. 



Tlie small pastern bones rest upon two bones, tlie coffin, or 

 OS pedis, and the navicular, or nut-bone, thereby formino- the 

 coffin joint. The coffin bone is the last phalange, and by means 

 of its connection comes in contact with the ground. It is a very 

 singular bone, both in its shape and construction, and will after- 

 wards demand our more particular consideration. It corre- 

 sponds in great measure to the horny hoof to which it is attached. 

 The navicular is a considerably smaller bone lying behind the 

 former, supporting a portion of the superincumbent weight, but 

 aflfording likewise an important pulley for the flexor tendon. 

 This pai't is the frequent seat of disease. 



The hind extremity of quadrupeds varies much from the fore 

 In the manner of its connection to the body. There is less 

 weight to support, and consequently there is less danger of con- 

 cussion ; but as more motion is required, the connection is 

 formed by means of a joint. 



Tiie upper bone, called the femur, has a large globular head, 

 which is received into a deep socket formed by the bones of the 

 pelvis, and this joint is secured from dislocation not only by 

 means of the capsular ligament, but likewise by one of immense 

 strength situated within the joint. The motion of this joint is 

 greater and the cavity deeper in the human subject ; but in the 

 horse the motion is chiefly limited to a backward and forward 

 course, there being but little in a lateral direction. Thus the 

 horse cannot, like the human subject, stretch his legs very wide 

 apart : but, however, neai*ly all the lateral motion that the horse 

 possesses in the hind extremities is possessed by means of this 

 joint, there being scarcely any aftbrded by any other. The 

 femur is the largest bone in the body, and is extremely irregular 



D 



