208 



THE EXTERIOR OF THE HORSE. 



be carried much more in advance when it is inclined than when it is 

 straight. 



Let us represent by AB and A / B / (Fig. 60) these two different directions ; by 

 BM and / M / two vertical lines drawn from the superior extremity of each 



FIG. 



shoulder; finally, by ACandA'C', equal amplitudes of the two scapular oscilla- 

 tions. It is assumed, by hypothesis, that AM^> A'M'. Whence it follows that 

 A M + ACis> A'M' + A / C', or, in other words, that MC is > M' C'. 



Therefore, for an equal arc described by the point of each shoulder, 

 the more inclined will carry the lower or distal extremity to a position 

 the more anterior. This will also allow a greater extension of the 



humerus, and the forearm will reach for- 

 ward to a point more in advance. It is 

 certain, a priori, that a straight shoulder 

 is capable of a greater oscillation forward, 

 but it must be remembered that the degree 

 of the scapular movements is the result 

 of the functional shortening of the ele- 

 vator muscles of the point of the arm. 

 This shortening alone gives the measure 

 of rotation, a measure which we know is 

 proportional to the muscular length. We 

 have sufficiently dwelt on this particular 

 point cl propos to the neck without again 

 making reference to it here. 



Another advantage of an oblique 



shoulder lies in the perpendicular incidence of the muscular jnsertions 

 (Fig. 61). 



FIG. 61. 



