22 Veterinary Elements. 



muscle is proportional to the degree of stimulation given 

 by its nerves, therefore, the more energetic in action, the 

 stronger, other things being equal. 



When speaking of muscles, the fixed end is the origin, 

 the part (or end) it moves, the insertion. Some of the 

 more important muscles are here taken up and their 

 actions, origins and insertions mentioned, those of the 

 limbs being of especial interest, as dealing with locomo- 

 tion. The first muscle seen after the removal of the skin 

 is [the one that twitches the skin, the fly-shaker, pan- 

 niculus carnosus, its boundaries are of no particular 

 interest, its actions are, assisting as it is said to, in the 

 expulsion of air from the lungs when highly developed, 

 seen in the race horse. 



When the foreleg is advanced, the shoulder joint is 

 extended and elbow joint flexed, when drawn back the 

 opposite takes place, due to the action of a powerful 

 muscle (pectoralis magnus) attached at one end to the 

 front of the shoulder blade, at the other to the head of 

 the bone of the fore arm, just below the level of the elbow 

 joint. Another powerful muscle (flexor brachii) attached 

 to the point of the shoulder blade and point of the elbow 

 flexes (bends)the shoulder joint and straightens (extends) 

 the elbow joint. There are other minor muscles that 

 assist in these movements. Three muscles (flexor meta- 

 carpi externus, medius and internus) bend the knee, 

 they originate on the back of the arm just above the 

 elbow joint and are inserted to the bone at the back of 

 the knee (trapezium) and the splint bones. The two 

 muscles (extensor pedis and extensor suffraginis), which 

 straighten the fetlock, pastern and coffin joints, run down 



