26 THE AKMY HOKSE. 



The -flexor pedis perforatus of the hind leg originates at the 

 back and lower part of the femur. Its fleshy portion extends 

 about halfway down the tibia, then becomes tendinous, and 

 passes over the point of the hock, continues down the back of 

 the leg, and is attached in the same manner as the perforatus 

 of the front leg. Action, to extend the hock and .to flex the 

 fetlock and pastern. 



The gastrocnemius externus has a double origin at the lower 

 and back part of the femur and is inserted to the joint of the 

 hock. At the back part of the leg the tendon of this muscle 

 becomes closely associated with the tendon of the flexor pedis 

 perforatus, the two forming the tendon of Achilles^ or havi- 

 strhu/. 



The flexor pedis perforans of the hind leg originates at the 

 upper and back portion of the tibia. Above the hock it becomes 

 tendinous and passing down over the inner and back side of 

 the hock is attached to the os pedis in the same manner as the 

 l^crforans of the front limb. Action, to extend the hock and 

 to flex the joints below. 



Wide muscles are attached to other structures by broad bands 

 of strong white tissue instead of by tendons. 



The pannieulus carnosns (fly shaker) is a wide flat muscle 

 situated on the inner surface of the skin and coA'ering most of 

 the neck, sides of the chest, and belly. Action, to shake the 

 skin. 



The principal muscles of the back, loins, and haunches are 

 the Imigissimus dorsi, gluteus externus, gluteus maximus, and 

 gluteus internus. 



The longissimus dorsi is situated on the upper part of the 

 back and loins, and is the largest and most powerful muscle 

 in the body, occuj^ying the S2iace on either side of the dorsal 

 and lumbar spines. Is broad and fleshy at its origin in the 

 loins and becomes narrower as it proceeds forward. It is 

 attached to the front part of the pelvis (ilium), first two bones 

 of the sacrum, all of the lumbar and dorsal A^ertebrte, the 

 external surface of the last fifteen or sixteen ribs, and to the 

 last three or four cervical vertebrae. Action : It is brought 

 powerfully into play in kicking or rearing; it elevates the 

 hind or fore quarters, according as the fore or hind limbs are 

 on the ground. Acting on one side only, it bends the back 

 and loins laterally. 



