The forearm. 87 



of the bone with one hand and rotating the shaft with the 

 other, a fracture may be recognized which otherwise might 

 escape notice at the time of examination because of the 

 rather deep situation of the upper part of the bone. 

 Fracture of the Ulna The olecranon process may be torn 

 off from the shaft by the action of the triceps, or by a fall 

 directly on the process, and, when it occurs, the 

 amount of displacement will depend as much on the dis- 

 ruption of the ligaments as on the action of the triceps it- 

 self. 



Fracture of the Shaft of the Ulna. Here there will 

 not be much, if any, displacement of the upper fragment, 

 since the brachialis anticus and the triceps neutralize 

 one another; but the lower fragment will be drawn out- 

 wards towards the radius by the pronator quadratus. 



Fracture of Bath Bones. In this case the upper frag- 

 ment of the radius will be displaced, as described under 

 fractures of the radius, in accordance with the situation 

 of the break, and, while the upper fragment of the ulna 

 will not be affected to any extent, the lower fragment of 

 each bone will be drawn towards one another by the pro- 

 nator quadratus, and, if the direction of the break be 

 obliquely upwards and forwards then the lower fragments 

 will be drawn up in front of the upper fragments, but if 

 obliquely upwards and backwards the lower fragments 

 will be drawn upwards behind the upper fragment. This 

 drawing upwards of the lower fragments is the result of 

 the contraction of the flexor and extensor muscles, which, 

 arising above the fracture are inserted into the wrist or 

 the fingers. In the treatment of fracture of both bones, 

 frequent inspection and proper dressings are absolutely 

 necessary. The application of a roller bandage beneath 

 the splint is to be condemned, since it might press together 

 the bones with the result that the formation of the callus 



