<unk> : Ventral<unk> <unk>  bowed and dorsal<unk> <unk>  visible in a case of a nondisplaced fracture of the radius head which is not visible directly. A normal anterior<unk> <unk>  in a non-fractured arm. Anterior sail signs as well as posterior<unk> <unk>  in a child with a supracondylar fracture. A subtle radial head fracture with associated positive sail sign The<unk> , also known as the sail sign, is a potential finding on elbow radiography which suggests a fracture of one or more bones at the elbow. It is may indicate an occult fracture that is not directly visible. Its name derives from the fact that it has the shape of a spinnaker (sail). It is caused by displacement of the<unk> <unk>  around the elbow joint. Both anterior and posterior<unk> s exist, and both can be found on the same X-ray. In children, a posterior<unk>  suggests a condylar fracture of the humerus. In adults it suggests a radial head fracture. In addition to fracture, any process resulting in an elbow joint effusion may also demonstrate an abnormal<unk> . Increased intracapsular fluid is also seen in several conditions other than fracture and this produces the abnormal<unk> . (toxic synovitis, septic arthritis, Juvenile Rheumatoid Arthritis, osteomyelitis of the distal humeral physis and secondary septic joint). In these instances, history and clinical examination in addition laboratory results (WBC, ESR, CRP) will guide the provider in determining whether to treat the condition as an occult fracture or continue workup for other pathology. The<unk>  is invaluable in assessing for the presence of an intra-articular fracture of the elbow. An anterior<unk> <unk>  is often normal. However a posterior<unk> <unk>  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.
Fat pad sign
Silk-glove sign
Procerus sign
String sign
Bow and arrow sign
Matchbox sign
Air crescent sign
Hilum overlay sign