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A MANUAL OF VETERINARY PHYSIOLOGY 



must first be transferred to its fellow ; the elbow-joint is next 

 unlocked by a relaxation of the extensor muscles, which are 

 inserted into the ulna ; the biceps brachii (flexor brachii) next 

 contracts to carry the arm forward, and by so doing assists to 

 flex the elbow,* the flexor muscles of the back of the limb contract 

 in order to flex the foot and all the joints as high as the knee. 

 The column of bones being broken as described and the whole 



Fig. 193. — The Position of the 

 Column of Bones of the Fore- 

 Leg when the Foot makes Con- 

 tact with the Ground. 



Fig. 194. — The Position of the 

 Column of Bones of the Fore- 

 Leg preparatory to Final Pro- 

 pulsion. 



limb made flexible, it is carried forward, the thoracic portion of 

 the serratus magnus and trapezius pulling one angle of the 

 scapula backwards, and the latissimus dorsi flexing the humerus 

 on the scapula. The limb having been advanced sufficiently, 

 the flexible column of bones is once more made rigid. First the 



* At this moment it is lifting a weight of about 17J pounds (8 kilos) 

 in a riding-horse, this being the weight of the limb from elbow to foot, 

 exclusive of the shoe. 



