ANTERIOR MEMBER. 203 



the sterno-humeralis, directed obliquely outward, downward, and backward; 

 finally must be added the serratus magnus, which draws the dorsal angle of the 

 scapula downward and backward, as well as the dorsal trapezius. 



As soon as the member has completed its extension the elevation of its supe- 

 rior border, and consequently the lowering of the articular angle, is effected by 

 the trapezius, the rhomboideus (the proper elevator), and the angularis on the 

 one part, and the sterno-trochineus and the sterno-prescapularis on the other, and 

 the member is again brought into its primitive position. These two movements, 

 intimately associated, are executed actively by the muscles above named, and 

 passively by the weight of the body. 



The scapular play, it is needless to say, should be as easy, supple, 

 and extensive as possible. Nevertheless, there are some horses whose 

 shoulders, though regularly constructed, are unable to rotate with 

 sufficient freedom, and this limitation markedly restricts the move- 

 ments of the member. Such a shoulder is vulgarly called pegged. 

 (See Defects of the Gaits.) 



Length. — The most important phenomenon in the construction 

 of the shoulder is its length, or, in other words, its development 

 from the summit of the withers to its point. 



Two factors enter into the production of this dimension : the 

 height of the spinous processes of the first dorsal vertebra above the 

 scapular cartilage, and the length of the shoulder properly so called. 

 But as the variations of one of the elements of this region are not 

 always correlative with those of the other, it follows that the real 

 length of the shoulder is not strictly given by the distance from the 

 summit of the withers to the point of the arm. This restriction being 

 established, let us view the assigned limits of this length and the 

 advantages which follow its marked development. 



Bourgelat was the first one to mention that the distance comprised 

 between the summit of the head and the commissure of the lips 

 equals almost exactly the measurement of the shoulder from the 

 withers to the insertion of the neck on the breast.^ This is an observa- 

 tion which is quite accurate, as has been testified by some of the very 

 best authorities on such subjects, notwithstanding the active opposition 

 which it has received from the generality of hippotomists. Those who, 

 like ourselves, have taken the pains to verify by numerous measure- 

 ments the exactness of this fact, Colonel Duhousset anions them, 

 have somewhat modified it by saying that the entire length of the 

 head equals the distance from the summit of the withers to the point 

 of the shoulder. It is thus, at least, in the more beautiful and perfect 



1 C. Bourgelat, loc. cit., p. 204. 



