852 KNUCKLING IN FOALS. 



on the posterior portions of the joints, caused by continued volar 

 flexion, would check the growth of bone, while diminution in the 

 anterior portions of the joints would favour its production, and thus 

 tend to thrust the phalangeal joints more and more into a position of 

 volar flexion. The rapidity with which the condition yields to proper 

 treatment, however, seems to contradict this theory. 



Symptoms. The most important symptom is the abnormal 

 volar flexion of the fetlock- joint, No disease of the tendons or 



Fig. 486. — Double-sided " knuckling " in a two-year-old colt (from a photograph). 



muscles can be detected, though they appear tensely stretched when 

 the fetlock is upright, Where the condition is well developed, the 

 limb is incapable of bearing weight. The new-born foal rears itself 

 up, but may be unable to stand and may die from exhaustion, or 

 necrosis produced by lying (bed-sores). Sometimes the animals 

 stand on the front of the fetlock-joint, and thus produce open joint 

 or other serious injury. Where the appearance of the disease is 

 delayed the animals can stand, but move with difficulty, and after 

 some time show excessive uprightness of the hoof. The condition is 

 distinguished from contraction produced by tendinitis by the absence 



