294 



APPLIED ANATOMY. 



outer to the inner surface of the trochlea. The outer condyle then becomes promi- 

 nent while the inner becomes confused with the olecranon. The identity of the con- 

 dyles is always to be established by tracing them up the humerus. This dislocation 

 is always incomplete. 



Treatment. Extension and counterextension with the arm slightly flexed to 



FIG. 308. Anterior dislocation of the head of the radius. (From author's sketch.) 



release the coronoid process aided by direct pressure on the humerus inward and the 



ulna outward. 



Outward Dislocation of the Elbow. In outward dislocation the concave 



surface of the olecranon rests on the capitellum and in the groove between it and the 



trochlea. The head of the radius projects far to the outer side of the external condyle. 



The inner condyle and trochlea become quite prominent and can be readily recognized. 



Treatment. Slight flexure of the fore- 

 arm. Traction and pressure on the radius 

 inward and on the internal condyle and 

 lower end of the humerus outward. 



Dislocation of the Head of the 

 Radius. The ulna alone is rarely luxated 

 (when displaced it would practically be 

 a backward and inward luxation of the 

 elbow) but the head of the radius is not 

 infrequently pulled out of place (Fig. 308). 

 The accident occurs in children, par- 

 ticularly young ones who, in walking with 

 their elders, are frequently lifted or helped 

 along by a pull on the hand. The pull, 

 accompanied by hyperextension of the el- 

 bow and some adduction of the hand, draws 

 the head of the radius from beneath the 

 orbicular ligament and then the tension of 

 the biceps drags it forward. The displace- 

 ment may be either marked or slight. A 

 marked displacement in the well-developed 

 arm of an adult is readily recognized, but 

 in the fat, chubby, undeveloped arm of an 

 infant it is easily overlooked. 



Diagnosis. Pain attracts attention to 

 the part. There is apt to be inability to 

 flex the arm beyond a right angle, due to 

 the radius impinging on the lower end of 



FIG. 309. Anterior dislocation of the head of the 

 ius. Position of bones when viewed from in front. 



rad 



the humerus. Careful palpation reveals a 



hollow below the lateral (external) condyle which should be normally occupied by 

 the head of the radius. The outer side of the forearm at the bend of the elbow may 

 be abnormally full and pressure here may detect the head of the radius displaced 

 forward (Figs. 309 and 310). 



Treatment. The forearm is to be extended almost to a straight line. Pressure 

 is to be made with the thumb to force the head of the radius back into place. While 

 this is done the forearm is to be flexed on the arm and if the head is replaced the 



