208 



THE EXTERIOR OF THE HORSE. 



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

 straight. 



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

 BM and B^M^ two vertical lines drawn from the sujjerior extremity of each 



Fig. 60. 



shoulder; finally, by ^4 (7 and A^C, equal amplitudes of the two scapular oscilla- 

 tions. It is assumed, by hypothesis, that AMy A^M\ Whence it follows that 

 AM-\- A C is > 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 ca})able of a greater oscillation forward, 

 but it nnist be remembered that the degree 

 of the scapular mt)vements 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 a propoH to the neck without again 

 making reference to it here. 



Another advantage of an oblique 

 shoulder lies in the perpendicular incidence of the muscular insertions 

 (Fig. 61). 



Fig. 61. 



