296 APPLIED ANATOMY. 



tension of either the anterior or posterior muscles tends to favor overlapping and to 

 prevent replacement. Full flexion renders the triceps tense. To relax both sets of 

 muscles a position at about right angles is probably best. 



Stimson has shown that gunstock (angular) deformity frequently follows this 

 injury, hence especial care should be taken to guard against it. It is caused by a 

 tilting of the lower fragment. Instead of a line joining the condyles being at right 

 angles to the long axis of the humerus, it may be oblique, owing to one condyle 

 being higher than the other. Practically it is not possible to recognize this displace- 

 ment when the arm is bent at a right angle. The splints will fit the part and every- 

 thing appears satisfactory, but on removal of the splints and extension of the forearm 

 it may be found that the carrying angle has been destroyed and that a gunstock 

 deformity is present. This accident is to be avoided by extending the arm during 

 the earlier periods of treatment before the fragment becomes fixed by callus, and 



Triceps muscle 



Ulnar nerve 



Internal condyle 



Olecranon 



FIG. 311. Transverse fracture of the lower end of the humerus above the condyles. The upper fragment 

 is seen to be displaced forward and the lower fragment with the olecranon is displaced backward. This posterior 

 displacement is increased by tension of the triceps muscle. 



seeing that, on extension, the forearm makes the same angle with the arm as does 

 that of the healthy side. 



The common mode of treatment of supracondylar fractures is the use of antero- 

 posterior splints with th< ' elbow bent at a right angle or sometimes acutely flexed. 



Fr.actures Invol ng the Condyles. The condyles (page 280) have been 

 described as the lateral uony projections of the lower end of the humerus which are 

 extra-articular. Therefore the trochlea and capitellum are not parts of the condyles, 

 and the epicondyles are simply the tips of the condyles. 



Bearing this in mind it is evident that fractures involving the condyles may be 

 confined to them and not implicate the articular surfaces. They are then extra-artic- 

 ular fractures of the condyles, or they can with some reason be called fractures of the 

 epicondyles. Other fractures may not only implicate the condyles, but pass through 

 them into the articular surfaces. These will be called intra-articular fractures of the 

 condyles. The internal epicondyle (epicondylus medialis) is sometimes called the 

 epitrochlea. 



Extra-articular Fractures of the Condyles or Fractures of the Epicondyles. The 

 medial (internal) cond e projects far beyond the body of the bone as a distinct bony 



