Skeletal Trauma > Elbow > Radial Head Fracture

Radial Head Fracture

Radial Head Fracture
  • Most commonly caused by a fall on an outstretched arm.
  • Most common elbow fracture in adults.
  • Radial head fractures can be very subtle and the fracture line may occasionally not be visible on the radiograph. Non-displaced radial head fractures are especially difficult to observe on plain films.
  • Look carefully for a visible posterior fat pad sign. This indicates an elbow effusion. Fractures of the radial head may only be detectable by this fat pad sign. The anterior fat pad may also be useful, particularly when it has the appearance of a sail, termed the sail sign.
  • When there is strong clinical suspicion for a radial head fracture but a fracture is not apparent on a standard projection, a radial head view or CT may aid in diagnosis.  In an adult patient with elbow effusion after trauma, radial head fracture should be highly suspected or even assumed.
In the image below, look carefully for the sail sign. Being able to find this abnormality is helpful for diagnosing many radial head fractures.
Lateral view of elbow showing sail sign

Now look very carefully at the radiographs below. Notice that in the image on the left, both anterior and posterior fat pad signs are present. This should increase suspicion of a fracture. However, no fracture is apparent in this radiograph. The image on the right shows a different view taken from the same patient. In this view the radial head fracture is apparent.
Lateral view of elbow

Oblique view of elbow

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