18 Veterinary Elements. 



of the parts the stifle may be displaced outward, but not 

 inward; this displacement depends greatly on the state 

 of the lateral ligaments. The bone of the stifle receives 

 a number of ligaments and also muscles. The bones of 

 the lower thigh (tibia and fibula) articulate with the 

 other joint surface of the femur, the motion is that of a 

 hinge. The largest of these bones (tibia) is very bare 

 of musular covering on the inner side, an extra thick 

 covering of periosteum is there present, however; this 

 bone is sometimes broken by a kick, the breakage (frac- 

 ture) may not be noticed, the ends being held in place 

 by the strong periosteum, unless the animal is put to 

 work, when the ends become displaced and as a result 

 acute lameness, necessitating slaughter of the animal. 

 The fibula is small in the horse, in cattle and sheep is 

 represented by a fibrous (gristly) cord, in the pig it 

 extends the entire length of the tibia. 



The hock joint. The expanded end of the bone of the 

 lower thigh (tibia) meets the two large bones of the hock 

 (tarsus, ankle in man) and forms with this pulley surface 

 probably the most important joint, in animals, from the 

 horseman's standpoint, owing to the great amount of 

 work done and to the peculiar arrangement of the bones. 

 It is in the region of the hock that such diseases as curb, 

 spavin, bone and bog are found. This joint is known as 

 the true hock joint and is of the hinge variety, when 

 motion takes place the tendency is to turn the foot out- 

 wards in the direction of the pulley surface. The hock 

 is composed of six bones, arranged in rows, the upper 

 row containing the two main bones, os calcis and astrag- 

 ulus. The os calcis (the heel bone of man) has attached 



