80 LAMENESS IN THE HOR^E. 



perforatus, perforaus and teudiuoias iutersections of the 

 gastrociiemii, which pull the femur backward. In front 

 the flexor metatarsi envelopes the stifle, also assisting in 

 its extension. In this manner the equilibrium is almost 

 perfect, very little help of the muscles inserted about the 

 patella being required to maintain it. The propulsion of 

 the weight of the body depends on the three upper joints 

 and their powerful muscles. Vigorous extension of these 

 joints produces decided tightening of the flexor tendons of 

 the foot, pressing the toe and sole of the hoof against the 

 ground. This stretching of the flexors results in an elastic 

 gait and facilitates the beginning forward stride If the 

 extension of the hind-leg takes place slowly, as in a walk, 

 the body, so to speak, is pushed forward. Trotting and 

 galloping, calling for a more powerful and sudden extension 

 of the hind-leg, throws the body forward. 



At the moment the function of the supporting leg is 

 finished, all fasciae are tense, this being the primary factor 

 in introducing the function of the swinging leg, — that is, 

 the beginning of the forward stride. Now the ilio-psoas, 

 tensor fasciae lata, pectineus and sartorius act to advance 

 the leg, taking place under gradual flexion of all joints. As 

 soon as the hoof is perpendicularly under the hip-joint, the 

 further advance of the leg is accompanied by gradual 

 extension of all joints from the stifle down ; while the above 

 named muscles continue their action, the triceps femoris, 

 similar to the olecranian muscles of the fore-leg, assists in 

 the extension of the stifle and hock joints and forward 

 movement of the limb. The extensors of the hock and foot 

 are also concerned in this motion ; thus the hoof reaches the 

 ground, and the function of the supporting leg begins once 

 more. The function of the supporting leg is based upon 



