Anterior humeral line:

• Draw a line along the anterior aspect of the distal humerus on the lateral view. This line should intersect the middle of the capitellum. If it intersects the capitellum through the anterior third, or if it misses it entirely, it suggests a fracture with posterior angulation of the distal humerus.

Radiocapitellar line:

• On any view of the elbow, a line drawn through the middle of the radial shaft should pass through the capitellum. If the line misses the capitellum on any of the elbow views, dislocation of the radial head is present.