chap, xiii.] REGION OF ELBOW. 225 



constricted, and is transverse, following often the 

 line of the olecranon epiphysis. The amount of 

 displacement effected by the triceps varies, and de- 

 pends upon the extent to which the dense perios- 

 teum about the process and the ligaments that are 

 attached to it are torn. 



Fracture of the coroiioid process is an 

 extremely rare accident. It is impossible to under- 

 stand how the process can be torn off by the action 

 of the brachialis anticus, as some maintain, since that 

 muscle is inserted rather into the ulna at the base of 

 the projection, than into the process itself. Nor can 

 it be separated as an epiphysis, as supposed by others, 

 since it does not exist as such. 



Fractures of the head or neck of the radius 

 are rare, and occur usually with dislocation or other 

 severe injury. The head is commonly found split or 

 starred, and the lesion, if limited to the head, could 

 hardly be diagnosed. The upper epiphysis of the 

 radius is entirely within the limits of the annular 

 ligament, and could scarcely be separated in a simple 

 lesion. When the neck is broken (a very rare occur- 

 rence) the upper end of the lower fragment is drawn 

 well forwards by the biceps muscle. 



Resection of the elbow may be performed in 

 many different ways. In all procedures there is 

 danger of inflicting damage upon the ulnar nerve, and 

 some little difficulty often in clearing the prominent 

 internal condyle. If the knife be kept close to the 

 bone throughout the operation, no vessel of any 

 magnitude should be divided. The muscles most 

 disturbed during the resection are the triceps, 

 anconeus, supinator brevis, extensor carpi ulnaris, 

 extensor carpi radialis br^vior, and brachialis anticus. 

 It is most important to preserve the periosteum over 

 the olecranon, so that the triceps may still have some 

 attachments to the fore-arm after the joint is excised, 

 p 



