34 EQUINE ANATOMY. 



The upper extremity shows 



The head articulating with the acetabulum, forming two-thirds 

 of a sphere and a constriction externally, the neck. 



The great or external trochanter, outside and above, with a 

 summit, convexity and crest. 



The digital or trochanterian fossa, behind and below, receiving 

 the obturator muscles. 



The inferior extremity is flattened laterally and shows 



The external and internal condyles, separated by a notch behind, 

 with depressions for the crucial ligaments. 



The trochlea, a wide, smooth surface between the condyles 

 anteriorly, on which the patella glides. 



A fossa for muscular insertion outside the preceding. 



Rough spots outside each condyle, for muscular and ligament- 

 ous insertion. 

 Articulations, 3. 



Os innominata, patella and tibia. 



THE LEG. 



This consists of three bones, the tibia, fibula (or peroneus) and 

 patella (or knee-pan). 



THE TIBIA. 



The tibia is a long bone. Its general direction is downward 

 and backward, and has a shaft and upper and lower extremity. 



The shaft has three borders and three surfaces. 



The anterior border is sharp above, and known as the tibial 

 crest. 



The external border is concave above, forming part of the tibial 

 arch. The internal border is thick. 



The external surface is concave above, convex below, giving 

 origin to the fleshy part of the flexor of the metatarsus. 



The internal surface presents above, muscular imprints for the 

 adductors and semi-tendinosus. 



The posterior surface is divided, by an oblique line, into two 

 portions, the upper giving attachment to the popliteus, the lower 

 to the perjorans. 



The superior extremity shows 



An anterior tuberosity, separated from the external by the groove 



