14 LIVE-STOCK JUDGING 



with articular or joint surfaces by means of which one 

 bone moves on the other. By the operation of the joints 

 the columns are broken, the legs alternately flexed or 

 extended, and locomotion is thus accomplished. The joint 

 surfaces are maintained in position by the joint capsule 

 and lubricated by the synovia secreted by it. 



16. The muscular system. — The skeletal muscular 

 system is composed of the striated, voluntary variety of 

 muscle tissue. Some individual muscles are long and 

 thin, some short and thick, and others broad and flat. 

 They are arranged mostly in groups of those having similar 

 action, and may be in two or more superposed layers. 

 While the primary function of the muscles is to operate 

 the bones, they serve a secondary purpose in furnishing, as 

 it were, the skeleton, giving form to what would other- 

 wise be but a framework. This is much more marked in 

 some parts than in others. The head, for instance, is 

 but little altered in form or proportions from those of the 

 skull, while all but the column of the neck is muscle, giving 

 it a much better outline than it has in the skeleton; the 

 form of the withers of the horse is but slightly altered by 

 the muscles of that region, while the croup is made up of 

 such a mass of muscle as to completely change the skeletal 

 outline of that part. 



17. The structure and arrangement of individual 

 muscles. — Each muscle has, in its relation with the 

 bones, an origin where the fibers are attached directly 

 to a considerable area of bone surface, and an insertion 

 which is usually accomplished by means of a tendon into 

 which the muscle fibers are continued. The tendon may 

 have more length than the muscle itself, transmitting the 

 power of the muscle a considerable distance before it is 

 finally inserted. The extensors and flexors of the foot, for 



Digitized by Microsoft® 



