22 CHE \K.\lY BORSE IN ACCIDENT AND DISEASE. 



Tendons are white, round or flattened cords affixed to the ex- 

 tremities of long muscles, attaching them to other structures, but 

 themselves neither stretching nor contracting. 



All leg muscles are long muscles. Extensors are those that have 

 the power of straightening the limb; flexors, of bending the limb. 



The (xitnsor pedis is the principal extensor of the fore leg; it 

 originates at the lower extremity of the humerus, and its fleshy por- 

 tion continues to the lower third of the radius; at this point it be- 

 comes tendinous, and, passing down over the knee, continues along 

 the front of the \v^ and becomes attached to the upper and front 

 part of the os pedis. Action, to extend the leg. 



The extensor mffraqinis has its origin from the external head and 

 outer border of the radius and from the side of the ulna ; it is inserted 

 (attached) to the upper and front part of the os suflraginis. Action, 

 to extend the foot. 



The extensor metacarpi magnus has its origin from the lower and 

 external surface 1 of the humerus, passes down the front of the radius 

 and kneejoint, and is attached to the upper end of the large meta- 

 carpal bone. Action, to extend the metacarpus. 



The flexor oracliii has its origin from the lower end of the scapula, 

 near the shoulder joint, and passes down in front of that joint and 

 the humerus and becomes attached to the upper front part of the 

 radius. Action, to flex the elbow joint and extend the shoulder. 



The flexor pedis perforatus originates from the inner and lower part 

 of the humerus; it passes down the back part of the leg, becoming 

 tendinous just above the carpus; behind the pastern it bifurcates, 

 forming a ring for the passage of the tendon of the perforans and 

 becomes attached to the sides of the os corona?. Action, to bend or 

 flex the knee, fetlock, and pastern. 



The flexor pedis perforans originates with the perforatus ; its fleshy 

 portion passes down and is attached to the back part of the radius; 

 its tendinous portion, beginning at the knee, passes down the leg 

 between the cannon bone and the tendon of the perforatus, over the 

 back of the fetlock, through the arch formed by the division of the 

 tendon of the perforatus, and is attached to the under surface of the 

 os pedis. Action, to flex the knee and all joints below. 



The extensor pedis of the hind leg originates from the lower and 

 front part of the femur; its fleshy portion extends downward along 

 the front surface of the tibia to the hock, where it becomes tendinous; 

 passing thence down the front of the leg it is attached in the same 

 manner as the extensor pedis of the front leg. Action, to extend the 

 leg and flex the hock. 



The peroneus has its origin from the external ligament of the stifle 

 and from the outer part of the fibula, and is attached to the tendon 



