72 Anatomy Applied to Medicine and Surgery. 



semi-flexed, but that it will be on a lower level than that 

 process when the arm is fully flexed. The distance be- 

 tween the two bones is the best guide, however. Nor- 

 mally, one finger can be placed in the fossa between the 

 olecranon and the internal condyle, but in dislocation of 

 both bones backwards, two or more fingers may be so 

 placed. Another means of distinguishing fracture from 

 dislocation is that, in the case of dislocation, the de- 

 formity is lessened when the forearm is extended, where- 

 as in fracture, the deformity is increased under similar 

 circumstances. The explanation of this is, that, when 

 the forearm is straightened in displacement, the beak of 

 the olecranon sinks in towards the shaft, thus diminish- 

 ing the bulk of the projection, whereas in fracture, the 

 movement of extension of the forearm occurs through 

 the seat of the fracture and not at the joint, so that the 

 lower fragment and the olecranon, together, become 

 more prominent posteriorly. Lastly, in fracture, we have 

 seen that the internal condyle approaches the acromion, 

 while, in dislocation, it lemains at its normal distance 

 from that process. 



Excision of the elbow joint. In this operation a ver- 

 tical incision is employed so as to preserve, as far as pos- 

 sible, the function of the triceps, for, though the fibres of 

 the muscle may be severed, yet the retention of the 

 band of fascia that is prolonged from the outer side of 

 the tendon to the deep fascia of the forearm, permits a 

 certain amount of extension after the operation. Again, 

 the presence of the ulnar nerve in the fossa between the 

 internal condyle and the olecranon must be borne in 

 mind so as to avoid wounding it during the operation. 



