<prompt> Fallen fragment sign is a feature of -Simple bone cystAneurysmal bone cystGiant cell tumorFibrous dysplasia  <response>: Ans. is a i.e., Simple bone cyst Simple bone cvst SolitervUnicameral bone cysto Simple bone cyst occurs before the age of 20 yearso The most common site is proximal humerus 50followed by Proximal femur 25-30.o Radiological features are : -ConcentricMetaphysealExpansile lucent lyticWell defined border with sclerotic marginFallen Fragment sign : - Cortical fragment ofpathological fracture settles in the most dependent portion.Hinged fragment sign : - Sometimes fractured fragment does not separate from adjacent cortex. 