KNBS, FBTI^OCK, ANKLB, AND FOOT. 173 



and frog, for the purpose of receiving the downward pressure of the column 

 cf bones and to destroy shock. 



I/ateral Cartilages. These are attached, one on either side, to the 

 wings of the coffin bone by their inferior borders. They are thin plates 

 of fibro-cartilage, and their function is to assist the frog and adjacant 

 structures to regain their proper position after having been displaced by 

 the weight of the body while the foot rested on the ground. 



Joints. The contact of two or more bones so arranged, that they 

 move one upon the other either more or less is called a joint. In the 

 movable joints at the point of articulation are ligaments whose office is 

 the holding of the bones in position. There is as a result of the moving of 

 one part upon the other a certain amount of friction, and to insure easy 

 play and smooth movement of its parts nature has arranged a yellow, 

 oily, or glairy lubricant, called synovia, the last somewhat resembling 

 the white of an egg. 



This fluid is deposited in a containing sac, and the serous membrane 

 which forms the lining is the secreting organ. This membrane is of a 

 very sensitive nature, and while it lines the inner face of the ligaments 

 it is attached only upon the edges of the bones without extending upon 

 their length or between the layers of cartilage, which lie between the 

 bones and their articular surfaces. 



So long as the bones, the muscles and their tendons, the joints with 

 their cartilages, their ligaments and their synovial structure; the nerves 

 and the blood vessels which distribute to every part, however minute, 

 are exempt from disease, and pathological change, the function of mo- 

 tion will continue to be performed with perfection and efficiency. 



But on the other hand, let any element of disease become implanted 

 in one or several of the parts destined for combined action, any change 

 or irregularity of form, location or action occur in any portion of the 

 apparatus, any obstruction of vital power take place, any interference 

 with the order of normal nature, any loss of harmony and lack of bal- 

 ance, and the result is lameness. 



Description of the Manikin. The outside plate on the right of 

 page 168, shows the part of the leg between the knee and the fetlock 

 joint in a healthy condition. The second plate of this series shows 

 a DIFFUSE SPLINT, bony growth with a diffuse base, in which, the bone 

 has permanently assumed greater size. This is a serious difficulty on 

 account of the deformity interfering with the movement of the cord 

 which passes behind it, thereby becoming a source of continual irritation 

 and consequently permanent lameness. 



