166 THE HORSE 



The bones composing the haunch, or hind-quarters, have 

 already been mentioned, and together with those of the 

 hind-leg maybe recapitulated (Plate III.) : — 



A Sacrum j 



^ ^^^"^" } Pelvis 



C Ischium I 



D Pubis * 



E Femur, or Upper bone of the thigh. 



P Patella, or Knee-cap. 



G Tibia, or Thigh. 



H P^ibula. 



I Tarsus, or Hock. 



K L Metatarsus, or Shank and Splint-bones. 



M Sesamoids. 



while the upper and lower pasterns, (o) and (q) the coffin- 

 bone (P), and the navicular-bone (K), resemble those of the 

 fore-limbs. 



Beginning at the upper extremity of the hind-leg, the 

 first bone to be noticed is the femur, or true thigh, or, as it 

 is usually termed, the upper bone of the thigh. It is 

 entirely hidden by the various muscles of the haunch, and 

 is therefore not easily recognised. It is short, but 

 exceedingly strong and stout, and at the upper extremity 

 has a distinctly rounded head on the inner side, fitting into 

 and articulating with the acetabulum, or bony cup formed 

 at the junction of the three pelvic bones. The lower end 

 of the bone has two prominences which fit into corresponding 

 depressions in the next bone, and in front of which is placed 

 the patella, or knee-cap (F), which together form the stifle- 

 joint. The tibia, the bone of which is known as the second 

 thigh, extends from the stifle-joint, which it helps to form, 

 to the hock, or tarsus ; and placed behind on the outer side 

 is the fibula, extending from its upper extremity to about 

 one- third of its length, and attached to the larger bone by 

 cartilage. In general character it agrees with the ulna, or 

 small bone of the elbow, in the fore-leg. 



The hock (tarsus) is an important and complicated joint, 

 and from its nature is frequently the seat of injury, 

 especially from shock or of strain. Like the knee, it consists 



