Elbow joint effusion (sail sign)

Case contributed by Assoc Prof Frank Gaillard




On lateral elbow radiograph, the anterior fat pad (which is intra-articular, but extra-synovial) becomes elevated due to joint effusion appearing as a triangle. This has been termed the sail sign due to the resemblance to the spinnaker of a sailboat. 

There is also on sagittal CT, the fat pads of the elbow become elevated due to joint effusion.

Case Discussion

There is elevated anterior fat pad of the elbow due to joint effusion which is called sail sign.

In adults, this is usually a radial head fracture whereas in children, the commonest cause of a raised elbow fat pad is a supracondylar fracture.  Where a fat pad is raised and no fracture is demonstrated, an occult fracture should be suspected.

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Case information

rID: 2657
Published: 7th May 2008
Last edited: 13th Aug 2019
Inclusion in quiz mode: Excluded

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