LAMENESS IN THE FORE LEG 127 



a collateral ligament occurs, recovery is slow and incomplete — • 

 there always results considerable exostosis at the site of injury. 



Sesamoiditis. 



Etiology and Occurrence. — Inflammation of the proximal 

 sesamoid Ijones is caused by any kind of irritation which may 

 involve this part of the inhibitory apparatus. Positioned as 

 they are, between the bifurcations of the suspensory ligament 

 and the pastern joint, they serve as fulcra and effectively assist 

 in minimizing concussion which is received by the suspensory 

 ligament. The flexor tendons also, in contracting, exert strain 

 upon the inter-sesamoidean ligament, which has a similar effect 

 upon the sesamoid bones as that which is produced by the sus- 

 pensory ligament. 



The condition occurs quite frequently, and because of the 

 important function performed by these bones, active inflamma- 

 tion of the sesamoids constitutes a serious affection. Because 

 of the fact that these bones have proportionately large articular 

 surfaces, when they are inflamed to the extent that degenerative 

 changes affect the articular cartilage, complete recovery seldom 

 results. 



The same pathological changes occur here that are to be seen 

 in any case of arthritis. No special pathological condition char- 

 acterizes sesamoiditis but this condition causes incurable lame- 

 ness when the sesamoid bones are much inflamed. 



Symptomatology. — In acute inflammation, there exist all tlie 

 symptoms which portray any arthritic inflammation of like char- 

 acter. The parts are readily palpable and are found to be hot, 

 supersensitive, and more or less infiltration of the tissues con- 

 tiguous to the joint causes swelling. There is volar flexion of the 

 phalanges when the subject is at rest. Lameness is intense ; in 

 some acute inflammatory disturbances the subject is unable to 

 bear weight on the affected member. 



In chronic sesamoiditis, constant lameness is the one salient 

 feature which marks the condition. While it is possible for one 

 sesamoid bone to become involved without its fellow being af- 

 fected, this is not usual. Considerable organization of tissue 

 surrounding the joint is present and no particular evidence of 



