MUSCLES ON THE OUTSIDE OF THE SHOULDER. 



259 



order to show other muscles beneath. A moment's inspection will convince thti 

 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 with- 

 ers ; otherwise, although there may 

 be height of withers, and obliquity 

 of shoulder, to give extensive action, 

 there will not be sufficient muscular 

 power to work the machine with 

 either quickness or continuance. 



At c is a portion of the levator 

 humeri (the raiser of the shoulder), 

 descending from the tubercle of the 

 head (see cut, page 68), 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 the 

 covering of the muscles of the shoul- 

 der, 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 rf 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 sur- 

 face 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 occasional!}' discharges another important 

 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 obsti- 

 nately stand night and day, in order that he may obtain the assistance of this muscle 

 in respiration, which is become laborious and painful ; and for the same reason it is 

 that we regard his lying down as one of the most favourable symptoms, because it 

 shows us that the breathing is so much relieved as not to need the assistance of this 

 muscle. 



At e is a small portion of the splenius muscle, which was spoken of when the neck 

 was described, p. 159. 



/ represents a muscle sometimes described as a portion of the levator humeri, or 

 elevator of the shoulder, arising from the nipple-shaped process or tubercle of the 

 temporal bone, running down the somewhat lateral but fore part of the neck, inserted 

 into the upper and middle ])art of the lower bone of the shoulder, and thence coa- 



