Ortho: Elbow

 

On an elbow X-ray, the fat pad sign, also known as the sail sign, suggests an occult fracture. Its name derives from the fact that it has the shape of a spinnaker (sail).^[1] It is caused by displacement of the fat pad around the elbow joint. Both anterior and posterior fat pad signs exist, and both can be found on the same X-ray.

In children, a posterior fat pad sign suggests a condylar fracture of the humerus. In adults it suggests a radial head fracture. The fat pad sign only occurs after an intra-articular fracture.





Knee fat pad sign (+): Push the soft tissue above th knee downwards and squeeze the fat pad -> pain