Sail sign

In radiology the sail sign is finding X-ray that suggests an abnormality.

Elbow X-ray
On an elbow X-ray that suggests an occult fracture. Its name derives from the fact that, with some imagination, it has the shape of a spinnaker (sail). It rises from displacement of the fat pad around the elbow joint. Both anterior and posterior sail signs exist and both can be found on the same X-ray.

In children, a sail sign suggest a supracondylar fracture of the humerus. In adults it suggests a radial head fracture.

Chest X-ray
On chest X-ray the sail sign suggests pneumomediastinum.