32 VETERINARY STUDIES 



bones. Insertion, on the outer surface of the inferior maxillary. 

 Action, elevates the lower jaw. Nerve supply, from a branch 

 of the fifth cranial nerve (trifacial). 



Practical application. — The student should now make prac- 

 tical observations for himself, recording as in previous lectures. 

 He may select at the teacher's discretion several short thick 

 muscles and several long slender ones, and should note locations, 

 attachments, and probable functions, and should make a state- 

 ment concerning the probable working efficiency of muscles of 

 these different types. This refers to the amount of load to be 

 moved and long or short distance of movement. 



Study a skeleton, and also a horse in motion, and note 

 how the horse pulls, or lifts a load. What occurs at the articula- 

 tions and how is this brought about? 



Study the location and size of muscles and the relations of 

 these considerations to body conformation. 



Note how the voluntary muscles supplement the bony frame- 

 work in giving conformation and type in shape of neck, smooth- 

 ness of shoulder, width of back and loin, type of quarter, fore- 

 arm, gaskin, lower thigh or "twist." 



Short, heavy muscles (bellies) produce powerful but short 

 action; long, slender muscles reverse this and give weak power 

 and long movement. 



Disorders are numerous. Wounds are common and repair 

 is only fairly good — partly by connective tissue in place of 

 the normal muscle. Sprains are similar in nature, symptoms, 

 and treatment to those described for ligaments in the preceding 

 chapter. 



Atrophy (sweeny), e.g., of the shoulder and hip muscle, is a 

 common disorder of muscle tissue. Treatment must remove 

 the cause, often a severe lameness elsewhere, and improve nutri- 

 tion of the wasted muscle by rich blood supply to it, by lini- 

 ment, blister, or irritating injections, for example. Muscle 

 tissue is subject to various disorders such as fatty infiltration of 

 the heart muscle in old and excessively fat horses and dogs. 



