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of the leg, and is attached in the same manner as th.Q nerforatus 

 is on the front leg. Action, to flex the hind leg. 



The Jie.vor pedis perforans of the hind leg originates at the 

 nppsr and back portion of the tibia. Above the ho3k it becomes 

 tendinous and passes down over the inner and back side of the 

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

 perforans of the front limb. Action, to flex the joints below 

 th3 hock. 



The pannicidns carnosus (fly shaker) is a flat muscle situated 

 on the inner surface of the skin, covering most of the neck, sides 

 of the chest, and belly. Action, to shake the skin. 



The principal muscles of the back and loins are the longissimus 

 dorsi, gluteus externus, gluteus maximus, and gluteus internus. 



The longissimi dorsi is situated on the superior part of the back 

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

 body, occupj^ing the space on either side of the dorsal and lumbar 

 spines. It is broad and fleshy at its origin in the loins and 

 becomes narrower as it proceeds forward. It is attached to the 

 anterior part of the pehi^s (ilium), first two bones of the sacrum, 

 all of the lumbar and dorsal vertebrae, the external surface of the 

 last fifteen or sixteen ribs, and to the last three or four cer^dcal 

 vertebrae. Action ; it is brought powerfully into play by kicking 

 and rearing, by elevation of the fore or hind quarters, according 

 to whether the fore or hind hmbs are fijsed. Acting singly, the 

 result is lateral flexion of the back and loins. 



Gluteus externus is a V-shaped muscle situated on the external 

 part of the croup. It originates on the anterior part of the pelvis 

 and at the second and third sacral spines. Insertion, to the upper 

 and outer part of the femur. Action, to draw the thigh outward. 



Gluteus maximus is a very large muscle, originating in the 

 lumbar region ; it is attached to the pelvis and sacrum and is 

 inserted on the upper and outer portion of the femur. Action, 

 to extend the femur on the pehds, and when the posterior limbs 

 are fix:ed, to assist in rearing. 



Gluteus internus is situated underneath the gluteus maximus 

 and above the hip joint. It originates from the shaft of the 

 ilium (anterior bone of the pelvis) , and is inserted by a tendon 

 to the superior part of the femur. Action, to draw the leg out- 

 ward and rotate it inward. 



