.SESAMOID LAMENESS. 873 



towards the ground, being no longer supported by its suspensory 

 ligament, but so long as the flexor tendons are intact the fetlock 

 does not reach the ground. The accident is distinguished from 

 rupture of the flexor pedis perforans by the normal position of the 

 hoof, the toe of which, in rupture of the tendon, is directed 

 upwards, so that it no longer touches the ground. In fractured 

 sesamoid there is excessive lameness, swelling, pain on pressure 

 over the fractured bone and sometimes slight crepitation. In 

 perfectly fresh fractures a depression may be felt between the pieces 

 of bone. 



The prognosis is unfavourable. Reposition and retention of the 

 broken parts are scarcely possible, the sharp edges of the fragments 

 may injure the articular surface of the metacarpus and wound the 

 flexor tendons, and callus formation is usually large and disfiguring, 

 frequently limiting flexion of the joint. 



Moller unsuccessfully treated a race-horse for several months, 

 and found on post-mortem examination that the broken pieces had 

 not united, and that the condition was substantially as above 

 described. Field claims to have seen recovery follow longitudinal 

 fracture of both sesamoid bones. On account of the great pain 

 accompanying fracture, excessive volar (upright pastern) or dorsal 

 flexion (oblique pastern) may later result. The first occurs when 

 pain is great and the limb is rested for a long time ; in other cases, 

 as when pain is slight and weight is placed on the foot during recovery, 

 excessive dorsal flexion results. Restoration of normal position 

 and of usefulness being very rare, treatment is only justifiable in 

 valuable breeding animals. 



Treatment. If treatment is to be attempted, the fetlock-joint 

 must be fixed in a position of moderate volar flexion by a plaster 

 or strong linen bandage ; a special shoe furnished with a ground 

 pillar to support the fetlock may be required. Complete rest is 

 necessary. Light horses, which have no difficulty in lying down 

 and rising, do best on a soft bed ; other patients must be slung. 



IV.— SESAMOID LAMENESS. 



In solipeds, both the anterior articular surface of the sesamoid 

 bones in contact with the metacarpus and the posterior surface over 

 which the flexor tendons glide are often the seat of acute or chronic 

 inflammation. Brauell, in 1845, first drew attention to inflammation 

 of the posterior surface, and pointed out that it was similar in 

 character to that of chronic navicular disease. Ten years later 



