TENDONS OF THE FLEXOR METATARSI MUSCLE 137 



have already referred to the antagonism which exists between the tendo- 

 Achilles and the flexor metatarsi. In any case of inabihty on the part of 

 the latter, whether such inability be due to detachment of its tendons 

 from the bones, to complete or partial rupture of the muscle, or simply to 

 a sprain of its tendon with more or less laceration of its fibres, there will 

 be a corresponding relaxation of the gastrocnemius muscle, with the result 

 that we have the characteristic "wobbling" of the tendo-Achilles. If the 

 superficial portion of the muscle is completely ruptured or the tendons of 

 insertion are detached, we have an extremely well-marked increase in the 

 tibio-metatarsal angle, and the hock becomes straightened. In all cases 

 flexion of the hock is restricted and the joint is carried stiffly. The 

 slight flexion which the animal is capable of bringing about in some 

 caies, is due to the action of the extensor pedis muscle which, in the 

 cases referred to, is not affected. 



Most frequently, however, the limb is picked up, dragged forwards 

 and let down again in a stiff and stilty manner which very closely 

 resembles the movement of an artificial limb. 



There is usually some swelling at the seat of the injury. This is 

 particularly so when the rupture occurs in the middle third of the 

 tendinous division, and part of the deep or muscular division is also 

 involved. From our superficial examination it will be recalled that 

 the muscular belly of the extensor pedis forms a prominent surface 

 landmark on the antero-external aspect of this region. More externally 

 another surface elevation, which is not so well marked, is formed by 

 the belly of the peroneus muscle. The flexor metatarsi is deeply seated 

 to these muscles. Injury leading to swelling of the flexor metatarsi, 

 although not directly altering the external conformation of the part, does 

 so indirectly, inasmuch as it causes greater prominence to be given to the 

 elevations caused by the two muscles mentioned. Gentle palpation of 

 the enlargements, therefore, may not reveal indications of pain, since the 

 muscles palpated may be in no way injured. The application of pressure 

 will, however, reveal the seat of injury to the underlying muscle. The 



