ANTERIOR MEMBER. 215 



describes an arc of a circle forward to increase the opening of the 

 scapulo-humeral angle. It is not, as our distinguished colleague, M. 

 Chenier,' has said, that the humeral extension is terminated at the end 

 of the phase of contact, but it is at the end of the elevation, when the 

 foot is being placed on the ground, that the two bones (humerus and 

 scapula) attain their maximum separation. The same phenomena are 

 true of the member of the opposite side ; the angle is closed by the 

 approaching of its branches until the step is about to be terminated, 

 when the arm is extended. 



Length. — We will not consider the details of this particular ele- 

 ment as we did in the case of the shoulder. The arm should be as 

 long as possible, relatively, in (^rder to give greater length to its 

 muscles which attach to the radius, and to permit its inferior extremity 

 to describe an arc of a larger circle. But its length will be defective 

 when it becomes excessive, — that is to say, disproportionate relative 

 to that of the shoulder. In this instance, as we have seen (see Fig. 58), 

 the arc which it describes is not augmented. The foot will pass over 

 a smaller space of the ground surface ; the movements are not executed 

 with freedom ; the animal is disposed to stumble and fall, at least, if 

 the shoulder be not long and oblique. It is therefore apparent that, 

 in relation with the latter region, the arm should be short to give the 

 necessary extent and rapidity to its oscillations. According to our 

 measurements, confirmed by those of MM. Colin and Duhousset, the 

 distance between the point of the shoulder and the centre of the 

 humero-radial articulation should be equal to one-half of the length 

 of the head in draught-horses. In rapid motors, like the trotter or the 

 running-horse, it is, on the contrary, nearly always longer. 



It is important to recognize this dimension from a point of view 

 purely artistic, because sculptors and painters, says Colonel Duhous- 

 set,^ have committed grave errors from antiquity even to the present 

 time. Nearly all represent the humerus too long, placing much too 

 high the point of the arm, which should not extend beyond the level 

 of the extremity of the sternum. 



While an exaggerated length of the arm constitutes a defect which 

 is not always compensated, its shortness also produces deficiencies of an 

 inverse order, and both are hinderances in that which concerns the rapid 

 gaits. If too short, it accomplishes an insufficient extension ; its mus- 

 cles contract feebly, and restrain the movements of the forearm ; the 



1 G. Ch^nier, Analyse de la premiere edition du present ouvrage, in Echo des soci6t6s et asso- 

 ciations v^terinaires, annee 1882. 



* E. Duhousset, Lecheval, Paris, 1881, p. 67. 



