FRACTURES OF THE HUMERUS. 763 



Fractures of the condyles are caused by treads, notably in dogs, 

 though similar cases have been seen in horses. Sometimes the 

 external, sometimes the internal condyle is broken off in consequence 

 of the supporting leg making a violent rotary movement, or the 

 free leg being excessively ad- or ab- ducted. In dogs such fractures 

 are produced by awkwardly jumping or falling from a chair or table. 

 Of twenty-six fractures of the humerus in dogs treated by Stockfleth, 

 seven were through the diaphysis and nineteen through the condyles. 



As a rule, diagnosis of fracture of the diaphysis offers no difficulty. 

 There is severe pain both when the animal stands on the limb and 

 when it moves ; swelling and abnormal mobility and crepitation 

 when the scapula is fixed ; the other bones of the limb are found 

 intact. In such cases there can be no doubt. It is more difficult 

 to detect fracture of the condyle. Sometimes the disconnected 

 condyle is movable, and there may be crepitation ; diagnosis is 

 easiest in the dog. On account of the anatomical construction of 

 the elbow-joint in dogs, the external condyle when broken off is 

 usually drawn upwards, whilst the internal becomes visible on the 

 inner side of the elbow-joint, and appears lower in position than 

 usual. This increased prominence of the internal condyle seems 

 to have given rise to a belief that in the dog it (the internal condyle) 

 is the more frequently fractured. In horses there is severe lameness 

 when the limb is carried, and inability to place weight on the foot. 

 The leg is adducted (turned in) in fracture of the extensor condyle, 

 and abducted (turned out) in that of the flexor. In the former case 

 the lower joints of the limb are excessively flexed, so that the front 

 of the hoof is in contact with the ground, owing to the relaxed 

 extensor muscles being loosened from their upper points of insertion. 

 During recovery, this abnormal position of the limb often suddenly 

 disappears, and if, in fracture of the flexor condyle, weight be then 

 placed on the foot, the knee is excessively extended, so that the 

 anterior surface of the limb appears concave ; this is particularly 

 noticeable during trotting, at the moment when weight is placed on 

 the foot. When accompanying abnormal flexion of the elbow-joint, 

 this symptom is explained by the relaxation of the flexor metacarpi, 

 consequent on loosening of its upper point of insertion. The same 

 is true of the flexor tendons in fractures of the inner condyle. 

 Otherwise this symptom only occurs in rupture of the flexors, or in 

 fractures of the pisiform bone, and is, therefore, of particular 

 diagnostic value. It does not occur in carnivora. 



Fissuring of the humerus, or fracture of the outer wall of the shaft 

 with depression of the broken part, can scarcely be diagnosed owing 



