234 THE HORSE. 



of the chest, and thus malrrially assists in the act of breathing. There, 

 fore, as we iiave stated when treating of that disease, a horse labourins 

 under inflammation of tiie lungs will obstinately stand night and day, that 

 he may obtain the assistance of this muscle in respiration, which is become 

 laborious and painful; and we regard his lying down as one of the most 

 favourable symptoms that can occur, because it shows us tliat the 

 breathing is so much relieved that he needs not the assistance of this 

 muscle. 



At e is a small portion of the splenious muscle, of which we have spoken 

 when describing the neck, p. 1.54. 



/represents a muscle sometimes described as a portion of the raiser of 

 the shoulder, arising from the nipple-shaped process of the temporal bone, 

 running down the somewhat lateral but fore-part of the neck, inserted into 

 the upper and middle part of the lower bone of the shoulder, and thence 

 continued down to the arm. Its office is to bend the head j or, the head 

 and neck being fixed, to elevate and bring forward the arm. It is in 

 powerful action when the horse is running at his speed with the head 

 projected. 



At ^ is a portion of the slerno-jnaxUlaris, or muscle common to the fore- 

 part of the chest and the lower jaw, and described at p. 156. 



li gives the principal muscle, extending from the shoulder to the lower 

 bone of the shoulder, and employed in drawing this bone towards the 

 «houlder-blade, and bending the whole of the limb. Exceedingly powerful 

 action is required from this muscle ; therefore it is very tendinous, and 

 inserted in such a direction as to act with great mechanical advantage, and 

 that advantage increased in proportion to the slanting of the shoulder. 



The muscle at ?, aniea spinalus (before the spine) is situated, as its name 

 would intimate, on the external part of the siioulder, before the spine or 

 ridge, and fills the whole of that space. It proceeds towards the bone of 

 the arm, and, dividing into two parts, is inserted into the two prominences 

 in front of that bone. It is a very strong muscle, and extends the arm and 

 carries it forward. 



The muscle ai j, poslea spinalus (behind the spine or ridge), occupies 

 that space. It likewise goes to the lower bone of the shoulder, and is 

 inserted into the outer and upper liead of the bone. It draws this bone 

 outward and upward. 



At A: is a muscle common to the breast and the shoulder-blade, and 

 called the liUle pectoral, or breast muscle. It arises from the breast-bone, 

 and reaches to the covering of the shoulder-joint and the muscles of the 

 shoulder. Its action, in common with that of a larger muscle, seen at m 

 {the great pectoral), is to draw back the head of the lower bone of the 

 shoulder and the lower part of t!ie shoulder-blade, and to make the latter 

 bone more upright. 



At q is the tendon of a very important muscle, the long extensor of the 

 arm, extending from the upper angle, and the posterior border of the 

 ehouldei'-blade, to tlie point of the elbow, and the inside of the arm, and 

 which will be presently described; and at r and s are the three divisions 

 of another muscle concerned in the same office, arising from the shoulder- 

 blade and the lower bone of the shoulder, and likewise attached to the point 

 of tlie elbow by a very strong tendon. 



This cut represents the muscles on the inside of the shoulder, and fore- 

 arm, rt is a very prominent one. It is called the pectoralis trarisversus 

 (the muscle crossing the breast). It arises from the first four bones of 

 the chest, and runs across to the inner part of the arm, and is in.serted 



