THE HORSE IN MOTION. 73 



ralis, by Legh. The other is called the adductor of the arm, b}' 

 Chauveau ; teres major, by Percivall ; and the great scapula kumeralis, 

 by Legh. One acts on the outer and the other on the inner aspect of 

 the humerus, at equal distances from the shoulder joint, and nearly one 

 third of the distance from the articulation ; one from the outer, and the 

 other from the inner surface of the scapula; and the weight of each is 

 one pound, while their length is the same. They cannot be conceived 

 as acting independently of each other, and it is useless to consider 

 what their function would be when so acting. Conjointly they are 

 neither adductors nor abductors, but flexors of the shoulder. While 

 the bone is thus flexed, the limb is brought forward by the mastoido 

 humeralis, which is inserted into the same ridge as the external of 

 these two muscles. 



When the time comes for a thorough revision of the names of the 

 muscles of the horse (and that time must come soon, for it is now con- 

 fusion worse confounded), it is to be hoped they will be determined by 

 their mechanical action without reference to the action of corresponding 

 muscles in man. The camera has now made the task comparatively 

 easy. When that time comes, these muscles should be known as the 

 flexors of the shoulder, internal and external. 



There are two flexors of the forearm. The flexor brachii is a short 

 tendinous muscle, originating from the lower anterior extremity of the 

 scapula, just above the centre of the shoulder joint, by a strong tendon, 

 which is developed into a patella-formed cartilage, moulded to the 

 double groove on the anterior angle of the humerus, over which it 

 glides as a synovial articulation, or a pulley, in the same manner as the 

 patella of the stifle joint, the grooves being deep so as to prevent 

 lateral displacement in extreme flexion. Below the shoulder it forms 

 a cylindrical muscle ten inches long. Its muscular fibres are inter- 

 mingled with tendinous bands, by which its elongation is limited, and 

 it is enabled to act as a ligament to support the weight of the body 

 without fatigue.* It is inserted into the capsular ligament of the 

 elbow joint,, and the rough tuberosity at the head of the radius. It 

 raises the forearm, and is one of the muscles on which, in part, the high 



* See description of serratus muscle, page 62. 

 10 



