Fat pad sign
![Fat pad sign: Ventral fat pad bowed and dorsal fat pad visible in a case of an undisplaced fracture of the radius head which is not visible directly.](/Images/godic/202502/03/Fettpolsterzeichen_pathologisch_Ellenbogen0548.png")
![A normal anterior fat pad in a non-fractured arm.](/Images/godic/202502/03/AnteriorFatPad0548.PNG")
![Anterior sail signs as well as posterior fat pad in a child with a supracondylar fracture.](/Images/godic/202502/03/Sailsign0548.PNG")
![A subtle radial head fracture with associated positive sail sign](/Images/godic/202502/03/Pradialheadfrac0548.png")
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). 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.