86 THE ANATOMY OF THE HORSE. 



ment of the most powerful muscles. From its upper ex- 

 tremity extends the neck {Skel. e), supporting the rounded 

 head {Skel. d), by which it is articulated with the pelvis. 

 Within the head is a cavity, giving origin to -djlat ligament, 

 which retains the hcEid of the bone in its situation : below 

 the head is inserted the capsular ligament. Upon the 

 middle of the inner side of the bone is a small eminence, 

 called the internal trochanter {Skel. h). Immediately in 

 front, and slightly behind the head of the bone, is a large 

 eminence, known as the great trochanter {Skel.f) ; below it 

 is a small projection, named the small external trochanter 

 {Skel. g). The use of each and of all these projections is 

 to give greater surface for attachment, and thus aid the 

 action of muscles. The lower end of the bone has two 

 large round surfaces or condyles {Skel. j). The stijle hone 

 {Skel. G) glides over the front of two prominences, called 

 trochlea {Skel. k). Behind the bone, above the condyles 

 previously mentioned, there is an indentation that affords 

 origin to the gastrocnemei muscles {Skel. i) which form the 

 calf of man. 



The stifle hone, ov patella {Skel. G), belongs to the class 

 of sessamoid bones, and is the largest in the body. This 

 order of bones are of a loose cellular structure ; having a 

 quantity of ligamentous fibre running through their interiors, 

 or mixed up with their bony material. They are of much 

 utility ; as they serve to aid motion ; and in the horse are, 

 save the patella, always found favouring the flexion of the 

 limbs. The stifle bone is of an irregular shape ; its outer 

 surface is roughened, for the insertion of numerous liga- 

 ments and tendons ; its inner surface articulates, or glides 

 over the front of the lower part of the femur ; its upper 

 border is connected with a powerful tendon, given off by a 

 muscle called the rectus ; and from its lower surface, which 

 is narrow or pointed, arises a muscle which serves to extend 

 the limb, — the flexor metacarpi magnus. So, on every side 

 that can bear attachment of a tendon, the patella, which is 

 not of more than the size of a man's palm, is connected 

 with muscles, or the organs of motion. Indeed the hind 

 leg cannot be moved in any direction without the stifle 

 changing its position. 



The tibia {Skel. H) is a large bone, situated within that 



