The fat pads in the elbow are a useful indicator of a joint effusion and underlying fracture. Lack of visualisation of the fat pads does not exclude fracture, however, if the posterior fat pad is seen on the true lateral radiograph, this indicates pathology as the fat pad should sit tucked away in the olecranon fossa. The anterior fat is usually visible, but should not be raised like a sail.
The first radiograph is normal. Note the abnormal elevated anterior fat pads (like a sail) and the posterior fat pads on the subsequent radiographs.