THE FORBAD ' ^"" 



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151 



v , 

 ing to take place posteriorly on either side of the ole- 



cranon, and anteriorly at the bottom of the fold at the 

 bend of the elbow. 



Fractures of the humerus, in the region of the joint, 

 frequently implicate it, and are to be distinguished from 

 dislocation by there not being the change in the normal 

 relation of three tuberosities viz., the olecranon, epi- 

 condyle, and epitrochlea. Almost any form of disloca- 

 tion may exist, but the most common is that of both 

 bones of the forearm backwards, the strength of the 

 lateral ligaments being a great obstacle to lateral dis- 

 placement. 



The dislocations to which the articulations of the 

 elbow-joint are liable are, in the first place, of both radius 

 and ulna, backwards, outwards, inwards, forwards; of 

 the radius only, forwards and backwards; and of the 

 ulna only, backwards. The difficulties in the diagnosis 

 of these several conditions are frequently enhanced from 

 the complication with fracture or separation of the 

 epiphyses, the union of which is as follows: the outer 

 condyle and both portions of the articulating portions of 

 the humerus at the sixteenth or seventeenth year, the inner 

 condyle at the eighteenth year, whilst the superior articu- 

 lar extremities of the radius and ulna unite with their 

 shafts at puberty. 



SURGICAL ANATOMY OF THE FOREARM. 



Surface Markings. The region of the forearm, or 

 antebrachial, may be described as lying between the 

 lower margin of that assigned to the elbow and the first 

 fold seen before the wrist-joint. In shape it is that of a 

 flattened cone, which varies in form according as the 



