THE MEMBERS. 



197 



1. Attenuation of Concussion. — This is effected during the 

 movement from to 2 by the diminution of the two extreme angles 

 (the scapulo-humeral and metacarpo-phalangeal) placed at the extremi- 

 ties of the rigid radio-metacarpal segment. The fetlock is strongly 



Fig. 55.— Action of the anterior member in the trot. 

 A. Phase of contact. | S. Phase of elevation. 



lowered and the radio-metacarpal segment piv^ots forward upon the 

 pastern, which is horizontal and immobile. During the second period, 

 from 1 to 2, the closure of the scapulo-liumeral angle is most marked. 



2. Extension of the Member. — Extension takes place in a 

 progressive manner from 2 to 3 (Fig. 55). The line of direction of the 

 member becomes vertical, elongated, and at the termination is directed 

 downward and backward. The angle of the fetlock and that of the 

 elbow are opened : the first by the gradual straightening of the pastern, 

 which pivots on the coronet and becomes vertical ; the second by 

 the forward rotation of the radio-metacarpal division, which pivots 

 upon the first phalanx. As to the angle of the shoulder, it becomes 

 slightly augmented by the forward rotation of the scapula. It is now 

 observed that during this period the member can fulfil a function of 

 impulsion, particularly when the resistance to progression is considera- 

 ble, as in strong traction, for example. 



Preparation for Elevation. — Elevation is manifested during 

 the movement from 3 to 4 (Fig. 55). The pastern continues to rotate 

 in advance, carrying with it the foot, which pivots upon its toe. The 

 radio-metacarpal angle becomes slightly flexed, while that of the 

 shoulder continues to augment. At the moment of elevation nearly 

 all the articular angles have reached their maximum extension. 



S. Phase of Elevation. — During this phase the foot leaves the 



