The fat pad sign is a sign that is sometimes seen on lateral radiographs of the elbow

Elbow

The human elbow is the region surrounding the elbow-joint—the ginglymus or hinge joint in the middle of the arm. Three bones form the elbow joint: the humerus of the upper arm, and the paired radius and ulna of the forearm....

 following trauma

Physical trauma

Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...

. Elevation of the anterior and posterior fat pads of the elbow joint suggests the presence of an occult fracture.

The fat pad sign is invaluable in assessing for the presence of an intra-articular fracture of the elbow. A anterior fat pad is often normal. However a posterior fat pad seen on a lateral x-ray of the elbow is always abnormal. The patient will be unable to flex their elbow and requires orthopaedic input.