330 



MUSCLES ON THE OUTSIDE OF THE SHOULDER. 



illustrating the advantage of high withers and a slanting shoulder. A portion 

 of it is represented as turned back, in order to show other muscles beneath. A 



moment's inspection will con- 

 vince the reader that although 

 a low forehand and thick 

 shoulder are very properly 

 objected to, yet still some 

 fulness and fleshiness are 

 necessary, even about the 

 withers ; otherwise, although 

 there may be height of 

 withers, and obliquity of 

 shoulder, to give extensive 

 action, there will not be suf- 

 ficient muscular power to 

 work the machine with either 

 quickness or continuance. 



At c is a portion of the le- 

 vator humeri (the raiser of 

 the shoulder), descending 

 from the tubercle of the head 

 (see cut, page 108), and from 

 the base of the temporal bone, 

 and attaching itself to the 

 first four bones of the neck, 

 and to the ligament of the 

 neck ; inserting itself into tbe 

 covering of the muscles of 

 the shoulder, and those about 

 the point of the shoulder, and 

 at length terminating in a 

 ridge on the body of the 

 humerus, arising from the 

 greater tubercle. It is a 

 muscle of immense power 

 and great utility, raising and 

 drawing forward the shoulder 

 and the arm, or, when these are fixed, turning the head and neck if one only 

 acts, and depressing them if the muscles on both sides act at the same time. 



At d is a portion of the serratus magnus muscle, between the shoulder and 

 side of the chest, and constituting the bulk of the lower part of the neck. It 

 is deeply seated, arising from the fourth, fifth, sixth, and seventh bones of the 

 neck anteriorly, and attached posteriorly to the eight first ribs. All its fibres 

 tend towards and are inserted into the inner surface of the shoulder, and by 

 means of them the shoulder is attached to the chest, and the immense weight 

 of the body supported. The use of this muscle in obviating concussion, has 

 already been spoken of. 



When the horse is standing, this muscle occasionally discharges another im- 

 portant function. The shoulders and legs are then rendered fixed points by the 

 weight of the body, and this muscle exerts all its power in dilating the cavity of 

 the chest, and thus materially assists in the act of breathing. Therefore, as was 

 stated when that disease was treated of, a horse labouring under inflammation of 

 the lungs will obstinately stand night and day, in order that he may obtain the 

 assistance of this muscle in respiration, which is become laboiious and painful ; 



