How may subtle supracondylar fractures of the elbow be diagnosed?
Pediatric elbow fractures often occur in the supracondylar region, where the humerus is relatively flat. The anterior humeral line, drawn on the lateral view of the elbow along the anterior humerus, normally intersects the middle third of the capitellum. This intersection is likely to be disrupted in supracondylar fractures. The presence of a joint effusion (hemarthrosis) is also extremely helpful and can be assessed by the presence of an elevated posterior fat pad, which is displaced and visible on the lateral view if there is blood in the joint. Displacement of the anterior fat pad (“sail” sign) may also be seen with hemarthrosis, but this finding is less specific.