Radial head fracture

Case contributed by Frank Gaillard
Diagnosis certain


Fall onto outstretched hands.

Patient Data

Age: 35 years
Gender: Male

Right elbow x-rays


A sizable joint effusion indicates a probable fracture, most likely through the radial head. The fracture itself is not clearly visualized.  Suggest re x-ray in 7 to 10 days.

Annotated image

The anterior fat pad sign, also known as the sail sign or spinnaker sign is the result of a joint effusion (yellow) elevating the normal anterior fat pad up and out of its normal location in the concavity of the humerus, which takes on a triangular shape (blue) on lateral projection.  

Rt elbow x-rays 10 days later


Radial head fracture is now visible (best seen on oblique view) with a persistent small effusion. 

Annotated image

Persistent sail sign (blue). Cortical breach on the anterior aspect of the radial head is now visible. Articular fracture is presumably present but is undisplaced and occult.

Case Discussion

Importance of recognizing a joint effusion as a marker of undisplaced radial head fracture. 

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